cmd-attach-session: redraw pane styles when changing active pane

Call window_redraw_active_switch() before selecting a pane so differing window-style and window-active-style colours are updated immediately.\n\nAdd a regression test for selecting a pane through attach-session.

CHANGES

@@ -130,8 +130,6 @@ CHANGES FROM 3.7c TO 3.8
 
 * Add capture-pane -I to include the time each line entered history.
 
-* Various memory leak fixes from Heon Jeong.
-
 * Add a default C-b T binding to change the current pane title.
 
 * Menus now belong to the window, so appear on all clients.

cmd-attach-session.c

@@ -91,8 +91,10 @@ cmd_attach_session(struct cmdq_item *item, const char *tflag, int dflag,
 	wp = target.wp;
 
 	if (wl != NULL) {
-		if (wp != NULL)
+		if (wp != NULL) {
+			window_redraw_active_switch(wp->window, wp);
 			window_set_active_pane(wp->window, wp, 1);
+		}
 		session_set_current(s, wl);
 		if (wp != NULL)
 			cmd_find_from_winlink_pane(current, wl, wp, 0);

cmd-join-pane.c

@@ -300,6 +300,7 @@ cmd_join_pane_mouse_move(struct client *c, struct mouse_event *m)
 	struct window_pane	*wp;
 	struct layout_cell	*lc;
 	int			 y, ly, x, lx;
+	int			 old_xoff, old_yoff, old_sx, old_sy;
 
 	wp = cmd_mouse_pane(m, NULL, &wl);
 	if (wp == NULL) {
@@ -321,10 +322,17 @@ cmd_join_pane_mouse_move(struct client *c, struct mouse_event *m)
 		ly = m->statusat - 1;
 
 	if (x != lx || y != ly) {
+		old_xoff = wp->xoff;
+		old_yoff = wp->yoff;
+		old_sx = wp->sx;
+		old_sy = wp->sy;
+
 		lc->g.xoff += x - lx;
 		lc->g.yoff += y - ly;
 		layout_fix_panes(w, NULL);
-		server_redraw_window(w);
+
+		window_pane_redraw_floating(w, wp, old_xoff, old_yoff, old_sx,
+		    old_sy);
 		server_redraw_window_borders(w);
 	}
 }

cmd-resize-pane.c

@@ -238,6 +238,7 @@ cmd_resize_pane_mouse_resize_move_floating(struct client *c,
 	int			 y, ly, x, lx, sx, sy, new_sx, new_sy;
 	int			 left, right;
 	int			 new_xoff, new_yoff, resizes = 0;
+	int			 old_xoff, old_yoff, old_sx, old_sy;
 
 	wp = cmd_mouse_pane(m, NULL, &wl);
 	if (wp == NULL) {
@@ -248,6 +249,10 @@ cmd_resize_pane_mouse_resize_move_floating(struct client *c,
 	lc = wp->layout_cell;
 	sx = wp->sx;
 	sy = wp->sy;
+	old_xoff = wp->xoff;
+	old_yoff = wp->yoff;
+	old_sx = (int)wp->sx;
+	old_sy = (int)wp->sy;
 	left = wp->xoff - 1;
 	right = wp->xoff + sx;
 	if (window_pane_scrollbar_reserve(wp) &&
@@ -347,7 +352,8 @@ cmd_resize_pane_mouse_resize_move_floating(struct client *c,
 	}
 	if (resizes != 0) {
 		layout_fix_panes(w, NULL);
-		server_redraw_window(w);
+		window_pane_redraw_floating(w, wp, old_xoff, old_yoff, old_sx,
+		    old_sy);
 		server_redraw_window_borders(w);
 	}
 }

cmd-split-window.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-split-window.c,v 1.151 2026/09/10 11:02:18 nicm Exp $ */
+/* $OpenBSD: cmd-split-window.c,v 1.150 2026/08/20 09:19:24 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -40,8 +40,8 @@ const struct cmd_entry cmd_new_pane_entry = {
 	.name = "new-pane",
 	.alias = "newp",
 
-	.args = { "AbB:Cc:Dde:EfF:hIkl:KLMm:Op:PR:s:S:t:T:vWx:X:y:Y:Z", 0, -1, NULL },
+	.args = { "AbB:Cc:de:EfF:hIkl:KLMm:Op:PR:s:S:t:T:vWx:X:y:Y:Z", 0, -1, NULL },
-	.usage = "[-AbCDefhIkKLMOPvWZ] [-B border-lines] "
+	.usage = "[-AbCdefhIkKLMOPvWZ] [-B border-lines] "
 		 "[-c start-directory] [-e environment] "
 		 "[-F format] [-l size] [-m message] [-p percentage] "
 		 "[-s style] [-S active-border-style] "
@@ -219,8 +219,6 @@ cmd_split_window_exec(struct cmd *self, struct cmdq_item *item)
 		new_wp->flags |= PANE_CAPTUREALLKEYS;
 	if (args_has(args, 'C') && args_has(args, 'O'))
 		new_wp->flags |= PANE_CLOSEONCLICK;
-	if (args_has(args, 'D') && args_has(args, 'O'))
-		new_wp->flags |= PANE_CLOSEONCANCEL;
 
 	style = args_get(args, 's');
 	if (style != NULL) {
@@ -362,6 +360,7 @@ cmd_split_window_mouse_resize(struct client *c, struct mouse_event *m)
 	enum pane_lines		 lines;
 	u_int			 sx, sy;
 	int			 x, y, xoff, yoff, border;
+	int			 old_xoff, old_yoff, old_sx, old_sy;
 
 	if (c->tty.mouse_last_pane == -1)
 		return;
@@ -417,8 +416,15 @@ cmd_split_window_mouse_resize(struct client *c, struct mouse_event *m)
 	if (sy < PANE_MINIMUM)
 		sy = PANE_MINIMUM;
 
+	old_xoff = wp->xoff;
+	old_yoff = wp->yoff;
+	old_sx = wp->sx;
+	old_sy = wp->sy;
+
 	layout_set_size(lc, sx, sy, xoff, yoff);
 	layout_fix_panes(w, NULL);
-	server_redraw_window(w);
+
+	window_pane_redraw_floating(w, wp, old_xoff, old_yoff, old_sx,
+	    old_sy);
 	server_redraw_window_borders(w);
 }

layout-custom.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: layout-custom.c,v 1.41 2026/09/09 09:01:19 nicm Exp $ */
+/* $OpenBSD: layout-custom.c,v 1.40 2026/09/09 07:03:39 nicm Exp $ */
 
 /*
  * Copyright (c) 2010 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -28,8 +28,8 @@
 #include "tmux.h"
 
 /*
- * Layouts can be represented as strings in a JSON format (v2). The version 1
+ * Layouts can be represented as strings in a JSON format (v2). The legacy
- * format will be removed in the future and should no longer be used.
+ * format (v1) will be removed in the future and should no longer be used.
  *
  * The current (v2) format is JSON. The top level has two keys:
  *    "V": version number, currently 2
@@ -57,9 +57,6 @@
  *    "z": z-index, if a floating pane
  */
 
-/* Maximum nesting depth for version 1 layouts. */
-#define LAYOUT_V1_MAX_DEPTH 1000
-
 /* Layout string. */
 struct layout_string {
 	char	*dat;
@@ -365,7 +362,7 @@ layout_append_v2(struct layout_cell *lc, struct layout_string *ls)
 	return (0);
 }
 
-/* Append information for a single cell in the version 1 format. */
+/* Append information for a single cell in the legacy (v1) format. */
 static int
 layout_append_v1(struct layout_cell *lc, struct layout_string *ls)
 {
@@ -781,7 +778,7 @@ layout_assign(struct window *w, struct layout_parse_ctx *pctx)
 		layout_assign_fallback(w, w->layout_root);
 }
 
-/* Construct a cell from the version 1 format. */
+/* Construct a cell from the legacy (v1) format. */
 static struct layout_cell *
 layout_construct_cell(struct layout_cell *lcparent, const char **layout)
 {
@@ -830,15 +827,12 @@ layout_construct_cell(struct layout_cell *lcparent, const char **layout)
 	return (lc);
 }
 
-/* Construct a layout from the version 1 format. */
+/* Construct a layout from the legacy (v1) format. */
 static struct layout_cell *
-layout_construct_v1(struct layout_cell *lcparent, const char **layout, u_int depth)
+layout_construct_v1(struct layout_cell *lcparent, const char **layout)
 {
 	struct layout_cell	*lc, *lcchild;
 
-	if (depth > LAYOUT_V1_MAX_DEPTH)
-		return (NULL);
-
 	lc = layout_construct_cell(lcparent, layout);
 	if (lc == NULL)
 		return (NULL);
@@ -861,7 +855,7 @@ layout_construct_v1(struct layout_cell *lcparent, const char **layout, u_int dep
 
 	do {
 		(*layout)++;
-		lcchild = layout_construct_v1(lc, layout, depth + 1);
+		lcchild = layout_construct_v1(lc, layout);
 		if (lcchild == NULL)
 			goto fail;
 		TAILQ_INSERT_TAIL(&lc->cells, lcchild, entry);
@@ -1074,8 +1068,7 @@ layout_construct(const char *input, struct layout_parse_ctx *pctx)
 			*pctx->cause = xstrdup("invalid layout checksum");
 			return (-1);
 		}
-		pctx->root = layout_construct_v1(NULL, &input, 0);
+		if ((pctx->root = layout_construct_v1(NULL, &input)) == NULL) {
-		if (pctx->root == NULL) {
 			*pctx->cause = xstrdup("invalid layout");
 			return (-1);
 		}

layout.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: layout.c,v 1.100 2026/09/11 08:16:14 nicm Exp $ */
+/* $OpenBSD: layout.c,v 1.99 2026/09/09 07:03:39 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -469,7 +469,6 @@ layout_fix_panes(struct window *w, struct window_pane *skip)
 					sx = PANE_MINIMUM;
 				else
 					sx = sx - sb_w - sb_pad;
-			wp->flags |= PANE_REDRAWSCROLLBAR;
 		}
 
 		window_pane_resize(wp, sx, sy);
@@ -477,8 +476,11 @@ layout_fix_panes(struct window *w, struct window_pane *skip)
 		if (wp->xoff != old_xoff ||
 		    wp->yoff != old_yoff ||
 		    wp->sx != old_sx ||
-		    wp->sy != old_sy)
+		    wp->sy != old_sy) {
 			changed = 1;
+			if (window_pane_scrollbar_reserve(wp))
+				wp->flags |= PANE_REDRAWSCROLLBAR;
+		}
 	}
 	if (changed)
 		redraw_invalidate_scene(w);
@@ -768,49 +770,6 @@ layout_free(struct window *w, int only_nodes)
 	layout_free_cell(w->layout_root, only_nodes);
 }
 
-/* Move and resize floating panes so they stay inside the window. */
-static void
-layout_clamp_floating_panes(struct window *w, u_int sx, u_int sy)
-{
-	struct window_pane	*wp;
-	struct layout_cell	*lc;
-	u_int			 pad, avail, csx, csy;
-
-	TAILQ_FOREACH(wp, &w->z_index, zentry) {
-		lc = wp->layout_cell;
-		if (lc == NULL || (~lc->flags & LAYOUT_CELL_FLOATING))
-			continue;
-		if (window_pane_get_pane_lines(wp) == PANE_LINES_NONE)
-			pad = 0;
-		else
-			pad = 1;
-
-		csx = lc->g.sx;
-		avail = (sx > 2 * pad) ? sx - 2 * pad : 0;
-		if (csx > avail)
-			csx = (avail > PANE_MINIMUM) ? avail : PANE_MINIMUM;
-		csy = lc->g.sy;
-		avail = (sy > 2 * pad) ? sy - 2 * pad : 0;
-		if (csy > avail)
-			csy = (avail > PANE_MINIMUM) ? avail : PANE_MINIMUM;
-		if (csx != lc->g.sx || csy != lc->g.sy)
-			layout_set_size(lc, csx, csy, lc->g.xoff, lc->g.yoff);
-
-		if (lc->g.xoff + lc->g.sx + pad > sx) {
-			if (lc->g.sx + 2 * pad >= sx)
-				lc->g.xoff = pad;
-			else
-				lc->g.xoff = sx - lc->g.sx - pad;
-		}
-		if (lc->g.yoff + lc->g.sy + pad > sy) {
-			if (lc->g.sy + 2 * pad >= sy)
-				lc->g.yoff = pad;
-			else
-				lc->g.yoff = sy - lc->g.sy - pad;
-		}
-	}
-}
-
 /* Resize the entire layout after window resize. */
 void
 layout_resize(struct window *w, u_int sx, u_int sy)
@@ -831,11 +790,8 @@ layout_resize(struct window *w, u_int sx, u_int sy)
 	 * out proportionately - this should leave the layout fitting the new
 	 * window size.
 	 */
-	if (lc->type == LAYOUT_WINDOWPANE && (lc->flags & LAYOUT_CELL_FLOATING)) {
+	if (lc->type == LAYOUT_WINDOWPANE && (lc->flags & LAYOUT_CELL_FLOATING))
-		layout_clamp_floating_panes(w, sx, sy);
-		layout_fix_panes(w, NULL);
 		return;
-	}
 	xchange = sx - lc->g.sx;
 	xlimit = layout_resize_check(w, lc, LAYOUT_LEFTRIGHT);
 	if (xchange < 0 && xchange < -xlimit)
@@ -865,7 +821,6 @@ layout_resize(struct window *w, u_int sx, u_int sy)
 
 	/* Fix cell offsets. */
 	layout_fix_offsets(w);
-	layout_clamp_floating_panes(w, sx, sy);
 	layout_fix_panes(w, NULL);
 }
 

options-table.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: options-table.c,v 1.246 2026/09/11 10:17:16 nicm Exp $ */
+/* $OpenBSD: options-table.c,v 1.244 2026/09/01 12:49:49 nicm Exp $ */
 
 /*
  * Copyright (c) 2011 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -76,8 +76,7 @@ static const char *options_table_pane_border_indicators_list[] = {
 	"off", "colour", "arrows", "both", NULL
 };
 static const char *options_table_pane_border_lines_list[] = {
-	"single", "double", "heavy", "simple", "number", "spaces", "none",
+	"single", "double", "heavy", "simple", "number", "spaces", "none", NULL
-	"rounded", NULL
 };
 static const char *options_table_popup_border_lines_list[] = {
 	"single", "double", "heavy", "simple", "rounded", "padded", "none", NULL
@@ -92,7 +91,7 @@ static const char *options_table_window_size_list[] = {
 	"largest", "smallest", "manual", "latest", NULL
 };
 static const char *options_table_remain_on_exit_list[] = {
-	"off", "on", "failed", "key", "failed-key", NULL
+	"off", "on", "failed", "key", NULL
 };
 static const char *options_table_destroy_unattached_list[] = {
 	"off", "on", "keep-last", "keep-group", NULL
@@ -1699,8 +1698,7 @@ const struct options_table_entry options_table[] = {
 	  .choices = options_table_remain_on_exit_list,
 	  .default_num = 0,
 	  .text = "Whether panes should remain ('on'), remain until a key is "
-		  "pressed after any exit ('key') or after a failure "
+		  "pressed ('key') or be automatically killed ('off' or "
-		  "('failed-key'), or be automatically killed ('off' or "
 		  "'failed') when the program inside exits."
 	},
 

popup.c

@@ -136,7 +136,8 @@ popup_reapply_styles(struct popup_data *pd)
 }
 
 static void
-popup_redraw_cb(const struct tty_ctx *ttyctx)
+popup_redraw_cb(const struct tty_ctx *ttyctx, __unused u_int py,
+    __unused u_int ny)
 {
 	struct popup_data	*pd = ttyctx->arg;
 
@@ -321,11 +322,60 @@ popup_resize_cb(__unused struct client *c, void *data)
 	}
 }
 
+/*
+ * Report damage for a popup's rectangle, given in raw client/tty
+ * coordinates. Status-line cells are outside the window scene - they have no
+ * corresponding window content and redraw_damage_window() can't reach them -
+ * so if the popup's rectangle overlaps the status line, force it to redraw
+ * separately. The rest of the rectangle is clipped to the actual pane area
+ * (above or below the status line, whichever side it's on) before being
+ * translated into window coordinates and reported the normal way, the same
+ * way mouse coordinates are translated elsewhere (e.g. cmd-join-pane.c,
+ * cmd-split-window.c).
+ */
+static void
+popup_damage(struct client *c, u_int px, u_int py, u_int sx, u_int sy)
+{
+	struct window	*w;
+	int		 statusat;
+	u_int		 ox, oy, osx, osy, lines, top, bottom, y0, y1;
+
+	if (c->session == NULL)
+		return;
+	w = c->session->curw->window;
+
+	lines = status_line_size(c);
+	statusat = status_at_line(c);
+	if (statusat >= 0 && py < (u_int)statusat + lines &&
+	    py + sy > (u_int)statusat)
+		c->flags |= (CLIENT_REDRAWSTATUS|CLIENT_REDRAWSTATUSALWAYS);
+
+	if (statusat == 0) {
+		top = lines;
+		bottom = c->tty.sy;
+	} else if (statusat > 0) {
+		top = 0;
+		bottom = statusat;
+	} else {
+		top = 0;
+		bottom = c->tty.sy;
+	}
+	y0 = (py > top) ? py : top;
+	y1 = (py + sy < bottom) ? py + sy : bottom;
+	if (y0 >= y1)
+		return;
+
+	tty_window_offset(&c->tty, &ox, &oy, &osx, &osy);
+	redraw_damage_window(w, px + ox, y0 - top + oy, sx, y1 - y0);
+}
+
 static void
 popup_handle_drag(struct client *c, struct popup_data *pd,
     struct mouse_event *m)
 {
 	u_int	px, py;
+	u_int	old_px = pd->px, old_py = pd->py;
+	u_int	old_sx = pd->sx, old_sy = pd->sy;
 
 	if (!MOUSE_DRAG(m->b))
 		pd->dragging = OFF;
@@ -348,7 +398,9 @@ popup_handle_drag(struct client *c, struct popup_data *pd,
 		pd->dy = m->y - pd->py;
 		pd->ppx = px;
 		pd->ppy = py;
-		server_redraw_client(c);
+
+		popup_damage(c, old_px, old_py, old_sx, old_sy);
+		c->flags |= CLIENT_REDRAWOVERLAY;
 	} else if (pd->dragging == SIZE) {
 		if (pd->border_lines == BOX_LINES_NONE) {
 			if (m->x < pd->px + 1)
@@ -375,7 +427,9 @@ popup_handle_drag(struct client *c, struct popup_data *pd,
 			if (pd->job != NULL)
 				job_resize(pd->job, pd->sx - 2, pd->sy - 2);
 		}
-		server_redraw_client(c);
+
+		popup_damage(c, old_px, old_py, old_sx, old_sy);
+		c->flags |= CLIENT_REDRAWOVERLAY;
 	}
 }
 

regress/attach-session-redraw.sh

@@ -0,0 +1,79 @@
+#!/bin/sh
+
+# Selecting a pane with attach-session from an already attached client must
+# redraw pane contents when window-style and window-active-style differ.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+DIR=$(mktemp -d) || exit 1
+INNER="$TEST_TMUX -Lattach-redraw-inner-$$ -f/dev/null"
+OUTER="$TEST_TMUX -Lattach-redraw-outer-$$ -f/dev/null"
+BEFORE=$DIR/before
+AFTER=$DIR/after
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		CLIENT=$($INNER list-clients -F '#{client_name}' 2>/dev/null)
+		[ -n "$CLIENT" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner client did not attach"
+}
+
+LEFT=$($INNER new-session -dPF '#{pane_id}' -s inner -x 40 -y 8 \
+    "printf 'LEFT'; exec sleep 100") || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+$INNER set-option -g default-terminal screen || exit 1
+$INNER split-window -h -t "$LEFT" "printf 'RIGHT'; exec sleep 100" || exit 1
+$INNER set-option -w -t "$LEFT" window-style bg=red || exit 1
+$INNER set-option -w -t "$LEFT" window-active-style bg=blue || exit 1
+$INNER bind-key -n x attach-session -t "$LEFT" || exit 1
+
+$OUTER new-session -d -s outer -x 40 -y 8 'sleep 100' || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+$OUTER set-option -g default-terminal screen || exit 1
+$OUTER respawn-pane -k -t outer:0.0 \
+    "$TEST_TMUX -Lattach-redraw-inner-$$ -f/dev/null attach-session -t inner" ||
+    exit 1
+
+wait_for_client
+sleep 1
+$OUTER send-keys -t outer:0.0 x || exit 1
+sleep 1
+[ "$($INNER display-message -p -t inner '#{pane_id}')" = "$LEFT" ] ||
+    fail "attach-session did not select the target pane"
+$OUTER capture-pane -pe -t outer:0.0 >"$BEFORE" || exit 1
+
+# A forced redraw produces the correct scene. It must be identical to the
+# scene drawn immediately by attach-session.
+$INNER refresh-client -t "$CLIENT" || exit 1
+sleep 1
+$OUTER capture-pane -pe -t outer:0.0 >"$AFTER" || exit 1
+cmp -s "$BEFORE" "$AFTER" ||
+    fail "attach-session left stale active/inactive pane styles"
+
+exit 0

regress/control-client-sanity.sh

@@ -30,11 +30,8 @@ killw
 EOF
 sleep 1
 $TMUX has || exit 1
-# Use a control client to request legacy layouts, keeping only pane lines
+$TMUX lsp -aF '#{pane_id} #{window_layout}' >$TMP || exit 1
-# from the control protocol output.
+cat <<EOF|cmp -s $TMP - || exit 1
-$TMUX -C lsp -aF '#{pane_id} #{window_layout}' |
-	grep '^%[0-9]' >$TMP || exit 1
-cat <<EOF|cmp $TMP - || exit 1
 %0 f5ab,200x200,0,0[200x50,0,0,0,200x149,0,51,3]
 %3 f5ab,200x200,0,0[200x50,0,0,0,200x149,0,51,3]
 %2 dcbd,200x200,0,0[200x100,0,0,2,200x99,0,101,4]

regress/floating-pane-drag-ghost.sh

@@ -0,0 +1,108 @@
+#!/bin/sh
+
+# Regression test for a floating-pane drag bug: cmd_resize_pane_redraw_floating()
+# (cmd-resize-pane.c) reported damage for just a dragged floating pane's
+# content rectangle, not the one-cell border frame drawn around it (see the
+# "floating" case in screen-redraw.c, which draws that frame at
+# xoff-1/yoff-1 through xoff+sx/yoff+sy - one cell outside the pane's own
+# content area). Damage scoped to only the content area left the frame's
+# previous position undrawn as the pane moved, so dragging it left a trail
+# of un-erased border frames behind - visible as several "corners" stacked
+# up rather than just the pane's current one.
+#
+# This bug has nothing to do with images - it reproduces with a plain
+# floating pane and no image support required.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+TMUX2="$TEST_TMUX -LtestB$$ -f/dev/null"
+
+cleanup()
+{
+	$TMUX kill-server >/dev/null 2>&1
+	$TMUX2 kill-server >/dev/null 2>&1
+}
+fail()
+{
+	echo "$*" >&2
+	cleanup
+	exit 1
+}
+
+# drag STARTCOL STARTROW ENDCOL ENDROW
+#
+# Write a plain (unmodified) SGR button-1 press, drag update and release at
+# 1-based positions to the outer pane holding the inner client - this
+# matches the default MouseDown1Border/MouseDrag1Border bindings used to
+# move or resize a floating pane by its border.
+drag()
+{
+	scol="$1"
+	srow="$2"
+	ecol="$3"
+	erow="$4"
+
+	seq=$(printf '\033[<0;%s;%sM' "$scol" "$srow")
+	$TMUX2 send-keys -t "$OUTER" -l "$seq" 2>/dev/null
+	sleep 0.2
+	seq=$(printf '\033[<32;%s;%sM' "$ecol" "$erow")
+	$TMUX2 send-keys -t "$OUTER" -l "$seq" 2>/dev/null
+	sleep 0.2
+	seq=$(printf '\033[<0;%s;%sm' "$ecol" "$erow")
+	$TMUX2 send-keys -t "$OUTER" -l "$seq" 2>/dev/null
+	sleep 1
+}
+
+cleanup
+
+TMP=$(mktemp)
+trap "cleanup; rm -f $TMP" 0 1 15
+
+$TMUX new-session -d -s inner -x 60 -y 20 'sh -c "sleep 100"' || exit 1
+$TMUX set -g mouse on
+$TMUX set -g default-command 'sh -c "sleep 100"'
+
+FLOAT=$($TMUX new-pane -d -PF '#{pane_id}' -x 16 -y 5 -X 5 -Y 5) ||
+	fail "new-pane -X -Y failed"
+FTOP=$($TMUX display-message -p -t "$FLOAT" '#{pane_top}')
+FLEFT=$($TMUX display-message -p -t "$FLOAT" '#{pane_left}')
+FWIDTH=$($TMUX display-message -p -t "$FLOAT" '#{pane_width}')
+
+$TMUX2 new-session -d -x 60 -y 20 "$TMUX attach -t inner" || exit 1
+sleep 1
+OUTER=$($TMUX2 list-panes -F '#{pane_id}' | head -1)
+[ -n "$OUTER" ] || fail "No outer pane."
+
+# Sanity check: exactly one floating pane, so exactly one top-left corner,
+# before dragging anything.
+$TMUX2 capturep -p -t "$OUTER" >$TMP || fail "capture failed"
+n=$(grep -o '┌' $TMP | wc -l)
+[ "$n" -eq 1 ] || fail "sanity: expected 1 corner before drag, found $n"
+
+# Drag the floating pane by its top border (row FTOP-1, some column within
+# its width) down several rows in a few separate steps, then release. A
+# single drag() call already does press/motion/release, so call it several
+# times in a row to simulate a multi-step real drag.
+GRABCOL=$((FLEFT + FWIDTH / 2))
+STARTROW=$FTOP
+i=0
+while [ $i -lt 6 ]; do
+	newrow=$((STARTROW + i + 1))
+	drag $((GRABCOL + 1)) $((STARTROW + i)) $((GRABCOL + 1)) $newrow
+	i=$((i + 1))
+done
+
+$TMUX2 capturep -p -t "$OUTER" >$TMP || fail "capture failed"
+
+# Exactly one top-left corner should remain - the pane's current position.
+# This is expected to fail before the fix: multiple corners (a trail of
+# un-erased frames) would remain from the intermediate drag positions.
+n=$(grep -o '┌' $TMP | wc -l)
+[ "$n" -eq 1 ] || fail "expected exactly 1 corner after drag, found $n (ghost frames left behind)"
+
+exit 0

regress/floating-pane-drag-scrollbar-strip.sh

@@ -0,0 +1,140 @@
+#!/bin/sh
+
+# Regression test: dragging a floating pane across another pane's ordinary
+# content must not redraw that other pane's scrollbar, unless the drag
+# actually crosses the scrollbar's own strip.
+#
+# cmd_resize_pane_redraw_floating() (cmd-resize-pane.c) used to flag
+# PANE_REDRAWSCROLLBAR on any pane whose whole *body* intersected the
+# floating pane's old or new rectangle, rather than just its narrow
+# scrollbar strip - so dragging a floating pane back and forth over an
+# ordinary tiled pane's content (never touching its scrollbar) still
+# needlessly redrew that pane's scrollbar on every motion step. See
+# tmux-image-redraw-known-bugs.md for the full write-up.
+#
+# This is checked by giving the non-dragged pane a distinctive scrollbar
+# colour and counting how many times its SGR code appears in the client's
+# raw output while the floating pane is dragged vertically over that pane's
+# body, well clear of its scrollbar column: with the fix, it should never
+# reappear after the initial draw.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+TMUX2="$TEST_TMUX -LtestB$$ -f/dev/null"
+
+cleanup()
+{
+	$TMUX kill-server >/dev/null 2>&1
+	$TMUX2 kill-server >/dev/null 2>&1
+}
+fail()
+{
+	echo "$*" >&2
+	cleanup
+	exit 1
+}
+
+# drag STARTCOL STARTROW ENDCOL ENDROW
+drag()
+{
+	scol="$1"
+	srow="$2"
+	ecol="$3"
+	erow="$4"
+
+	seq=$(printf '\033[<0;%s;%sM' "$scol" "$srow")
+	$TMUX2 send-keys -t "$OUTER" -l "$seq" 2>/dev/null
+	sleep 0.2
+	seq=$(printf '\033[<32;%s;%sM' "$ecol" "$erow")
+	$TMUX2 send-keys -t "$OUTER" -l "$seq" 2>/dev/null
+	sleep 0.2
+	seq=$(printf '\033[<0;%s;%sm' "$ecol" "$erow")
+	$TMUX2 send-keys -t "$OUTER" -l "$seq" 2>/dev/null
+	sleep 0.5
+}
+
+cleanup
+
+TMP=$(mktemp)
+trap "cleanup; rm -f $TMP" 0 1 15
+
+$TMUX new-session -d -s inner -x 60 -y 20 'sh -c "sleep 100"' || exit 1
+$TMUX set -g mouse on || fail "set mouse failed"
+$TMUX set -g default-command 'sh -c "sleep 100"' || fail "set default-command failed"
+$TMUX set -g pane-scrollbars on || fail "set pane-scrollbars failed"
+
+$TMUX split-window -h -t inner 'sh -c "sleep 100"' || fail "split-window failed"
+
+PANES=$($TMUX list-panes -t inner -F '#{pane_id} #{pane_left}')
+LEFT=$(echo "$PANES" | sort -k2 -n | head -1 | cut -d' ' -f1)
+[ -n "$LEFT" ] || fail "could not identify left pane"
+
+# A distinctive scrollbar colour for the non-dragged (left) pane only.
+$TMUX set -p -t "$LEFT" pane-scrollbars-style 'fg=colour201,bg=colour17' ||
+	fail "set pane-scrollbars-style failed"
+
+ALEFT=$($TMUX display-message -p -t "$LEFT" '#{pane_left}')
+ATOP=$($TMUX display-message -p -t "$LEFT" '#{pane_top}')
+AWIDTH=$($TMUX display-message -p -t "$LEFT" '#{pane_width}')
+AHEIGHT=$($TMUX display-message -p -t "$LEFT" '#{pane_height}')
+[ "$AWIDTH" -gt 15 ] || fail "left pane too narrow for this test ($AWIDTH)"
+
+# A small floating pane placed well inside the left pane's content area,
+# clear of its (right-hand) scrollbar column by several columns.
+FLOAT=$($TMUX new-pane -d -PF '#{pane_id}' -x 8 -y 5 \
+    -X $((ALEFT + 2)) -Y $((ATOP + 2))) || fail "new-pane -X -Y failed"
+FTOP=$($TMUX display-message -p -t "$FLOAT" '#{pane_top}')
+FLEFT=$($TMUX display-message -p -t "$FLOAT" '#{pane_left}')
+FWIDTH=$($TMUX display-message -p -t "$FLOAT" '#{pane_width}')
+[ $((FLEFT + FWIDTH + 3)) -lt $((ALEFT + AWIDTH)) ] ||
+	fail "sanity: floating pane too close to the scrollbar column"
+
+# Start the outer session with a plain shell, then start capturing before
+# triggering the attach - starting the attach as the outer pane's initial
+# command would mean pipe-pane only starts after the attach-driven initial
+# redraw (which draws the scrollbars) has already happened, missing it.
+$TMUX2 new-session -d -x 60 -y 20 || exit 1
+OUTER=$($TMUX2 list-panes -F '#{pane_id}' | head -1)
+[ -n "$OUTER" ] || fail "No outer pane."
+$TMUX2 pipe-pane -t "$OUTER" -O "cat >$TMP" || fail "pipe-pane failed"
+$TMUX2 send-keys -t "$OUTER" -l "$TMUX attach -t inner" || fail "send attach failed"
+$TMUX2 send-keys -t "$OUTER" Enter || fail "send enter failed"
+sleep 1
+
+# Sanity check: the distinctive scrollbar colour reaches the client at all.
+grep -qa '48;5;201' $TMP || fail "sanity: scrollbar colour never reached the client"
+: >$TMP
+
+# Drag the floating pane straight up and down by its top border, staying at
+# a fixed column the whole time - this never crosses the left pane's
+# scrollbar strip, only its ordinary content.
+GRABCOL=$((FLEFT + FWIDTH / 2))
+row=$FTOP
+i=0
+while [ $i -lt 6 ]; do
+	newrow=$((row + 1))
+	drag $GRABCOL $row $GRABCOL $newrow
+	row=$newrow
+	i=$((i + 1))
+done
+i=0
+while [ $i -lt 6 ]; do
+	newrow=$((row - 1))
+	drag $GRABCOL $row $GRABCOL $newrow
+	row=$newrow
+	i=$((i + 1))
+done
+
+# The scrollbar colour should never reappear - its geometry never changed,
+# and the drag never crossed its column. This is expected to fail before
+# the fix - see the header comment.
+n=$(grep -ac '48;5;201' $TMP)
+[ "$n" -eq 0 ] ||
+	fail "left pane's scrollbar was redrawn $n times while dragging over its body only"
+
+exit 0

regress/floating-pane-geometry.sh

@@ -268,149 +268,5 @@ $TMUX kill-pane -t "$floating" || exit 1
 $TMUX kill-pane -t "$right" || exit 1
 $TMUX kill-pane -t "$lower" || exit 1
 
-# --- Floating panes clamped when the window shrinks (issue #5581, PR #5582) ---
-#
-# layout_resize clamps floating panes back inside the window when it shrinks:
-# move them and, only if they cannot fit, shrink them (never below
-# PANE_MINIMUM). A floating cell is the pane's content, so with the default
-# single-line border the clamp counts 1 cell of border per side, exactly as
-# layout_floating_args_parse does on creation; with no border it counts 0.
-# Each case below gets its own window, since resize-window fixes a window at
-# a manual size for the rest of its life.
-
-# Case 1: a lone floating pane -- break-pane -W on a window's only pane --
-# takes the early-return path in layout_resize, added during PR #5582's
-# review round, since there is no tiled tree to walk.
-win=$($TMUX new-window -dPF '#{window_id}') ||
-	fail "new-window for lone float failed"
-
-# -x 20 -y 6 -> pane 18x4; -X 60 -Y 18 -> pane_left 61, pane_top 19: with the
-# border, the footprint is columns 60-79, rows 18-23, flush with the 80x24
-# window's right and bottom edges, so the float fits before it is shrunk.
-$TMUX break-pane -W -s "$win" -x 20 -y 6 -X 60 -Y 18 ||
-	fail "break-pane -W for lone float failed"
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_width}')"  18
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_height}')" 4
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_left}')"   61
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_top}')"    19
-
-# Shrink to 40x16. The float still fits at its own size (18 <= 40-2, 4 <=
-# 16-2) so only its position moves, flush to the new right/bottom edges:
-# xoff = 40 - 18 - 1 = 21; yoff = 16 - 4 - 1 = 11.
-$TMUX resize-window -t "$win" -x 40 -y 16 ||
-	fail "resize-window (lone float) failed"
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_width}')"  18
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_height}')" 4
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_left}')"   21
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_top}')"    11
-
-# Case 5: grow the window back. The clamp must not chase the window back
-# outward -- it only ever pulls a float in, never restores where it was.
-$TMUX resize-window -t "$win" -x 80 -y 24 ||
-	fail "resize-window grow (lone float) failed"
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_width}')"  18
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_height}')" 4
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_left}')"   21
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_top}')"    11
-$TMUX kill-window -t "$win" || exit 1
-
-# Case 2: the same float, but with a tiled sibling surviving alongside it, so
-# the window's root cell stays tiled and layout_resize takes the normal path
-# (the clamp call after layout_fix_offsets) instead of the early return
-# above. Same geometry as case 1, so the same numbers should come out.
-win=$($TMUX new-window -dPF '#{window_id}') ||
-	fail "new-window for tiled sibling failed"
-$TMUX split-window -t "$win" 'sleep 100' ||
-	fail "split-window for tiled sibling failed"
-$TMUX break-pane -W -s "$win" -x 20 -y 6 -X 60 -Y 18 ||
-	fail "break-pane -W for tiled sibling failed"
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_width}')"  18
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_height}')" 4
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_left}')"   61
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_top}')"    19
-
-$TMUX resize-window -t "$win" -x 40 -y 16 ||
-	fail "resize-window (tiled sibling) failed"
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_width}')"  18
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_height}')" 4
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_left}')"   21
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_top}')"    11
-$TMUX kill-window -t "$win" || exit 1
-
-# Case 3: new-pane float, the original repro from issue #5581 and the PR
-# body -- also the normal path, via the tiled base pane new-window creates.
-win=$($TMUX new-window -dPF '#{window_id}') ||
-	fail "new-window for new-pane repro failed"
-$TMUX resize-window -t "$win" -x 120 -y 40 ||
-	fail "resize-window to 120x40 failed"
-
-# -x 30 -y 10 -> pane 28x8; -X 85 -Y 25 -> pane_left 86, pane_top 26.
-floating=$($TMUX new-pane -t "$win" -dPF '#{pane_id}' \
-	-x 30 -y 10 -X 85 -Y 25 'sleep 100') ||
-	fail "new-pane for new-pane repro failed"
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_width}')"  28
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_height}')" 8
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_left}')"   86
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_top}')"    26
-
-# Shrink to 60x20: xoff = 60 - 28 - 1 = 31; yoff = 20 - 8 - 1 = 11.
-$TMUX resize-window -t "$win" -x 60 -y 20 ||
-	fail "resize-window (new-pane repro) failed"
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_width}')"  28
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_height}')" 8
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_left}')"   31
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_top}')"    11
-$TMUX kill-window -t "$win" || exit 1
-
-# Case 4: a float that already fits inside the shrunk window is left alone --
-# assert position and size are both unchanged, not just one of them.
-win=$($TMUX new-window -dPF '#{window_id}') ||
-	fail "new-window for untouched float failed"
-
-# -x 20 -y 6 -> pane 18x4; -X 8 -Y 3 -> pane_left 9, pane_top 4 (as at the top
-# of this file). Footprint columns 8-27, rows 3-8: well inside 60x20 too.
-floating=$($TMUX new-pane -t "$win" -dPF '#{pane_id}' \
-	-x 20 -y 6 -X 8 -Y 3 'sleep 100') ||
-	fail "new-pane for untouched float failed"
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_width}')"  18
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_height}')" 4
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_left}')"   9
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_top}')"    4
-
-$TMUX resize-window -t "$win" -x 60 -y 20 ||
-	fail "resize-window (untouched float) failed"
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_width}')"  18
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_height}')" 4
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_left}')"   9
-must_equal "$($TMUX display-message -p -t "$floating" '#{pane_top}')"    4
-$TMUX kill-window -t "$win" || exit 1
-
-# Case 6: pad = 0, via the pane-border-lines window option set to none. The
-# border arithmetic differs here (no -2/+1 adjustment either on creation or
-# in the clamp).
-win=$($TMUX new-window -dPF '#{window_id}') ||
-	fail "new-window for pad=0 float failed"
-$TMUX set-option -w -t "$win" pane-border-lines none ||
-	fail "set pane-border-lines none failed"
-
-# No border: -x 20 -y 6 -> pane 20x6 directly; -X 60 -Y 18 -> pane_left 60,
-# pane_top 18 directly. Footprint (== content, no border) is columns 60-79,
-# rows 18-23: flush right/bottom of the 80x24 window, same as case 1.
-$TMUX break-pane -W -s "$win" -x 20 -y 6 -X 60 -Y 18 ||
-	fail "break-pane -W for pad=0 float failed"
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_width}')"  20
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_height}')" 6
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_left}')"   60
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_top}')"    18
-
-# Shrink to 40x16 with pad=0: xoff = 40 - 20 - 0 = 20; yoff = 16 - 6 - 0 = 10.
-$TMUX resize-window -t "$win" -x 40 -y 16 ||
-	fail "resize-window (pad=0 float) failed"
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_width}')"  20
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_height}')" 6
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_left}')"   20
-must_equal "$($TMUX display-message -p -t "$win" '#{pane_top}')"    10
-$TMUX kill-window -t "$win" || exit 1
-
 $TMUX kill-server 2>/dev/null
 exit 0

regress/floating-pane-status-format.sh

@@ -0,0 +1,102 @@
+#!/bin/sh
+
+# Resizing a floating pane must refresh session status formats which depend on
+# its geometry, not only the pane scene and borders.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+DIR=$(mktemp -d) || exit 1
+INNER="$TEST_TMUX -Lfloating-status-inner-$$ -f/dev/null"
+OUTER="$TEST_TMUX -Lfloating-status-outer-$$ -f/dev/null"
+CAPTURE=$DIR/capture
+
+fail()
+{
+	echo "$*" >&2
+	[ -s "$CAPTURE" ] && cat "$CAPTURE" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		CLIENT=$($INNER list-clients -F '#{client_name}' 2>/dev/null)
+		[ -n "$CLIENT" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner client did not attach"
+}
+
+wait_outer_has_status()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		tail -1 "$CAPTURE" | grep -q "$marker" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "outer client status did not show $marker"
+}
+
+mouse()
+{
+	sequence=$(printf '\033[<%s;%s;%s%s' "$1" "$2" "$3" "$4")
+	$OUTER send-keys -t outer:0.0 -l "$sequence" || exit 1
+	sleep 0.1
+}
+
+$INNER new-session -d -s inner -x 50 -y 12 'sleep 100' || exit 1
+FLOAT=$($INNER new-pane -PF '#{pane_id}' -x 10 -y 5 -X 5 -Y 3 \
+    'sleep 100') || fail "could not create floating pane"
+$INNER set-option -g window-size manual || exit 1
+$INNER set-option -g mouse on || exit 1
+$INNER set-option -g status on || exit 1
+$INNER set-option -g status-position bottom || exit 1
+$INNER set-option -g status-left 'WIDTH=#{pane_width}' || exit 1
+$INNER set-option -g status-right '' || exit 1
+$INNER set-option -g status-interval 0 || exit 1
+
+$OUTER new-session -d -s outer -x 50 -y 12 'sleep 100' || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+$OUTER respawn-pane -k -t outer:0.0 \
+    "$TEST_TMUX -Lfloating-status-inner-$$ -f/dev/null attach-session -t inner" ||
+    exit 1
+
+wait_for_client
+OLD_WIDTH=$($INNER display-message -p -t "$FLOAT" '#{pane_width}')
+wait_outer_has_status "WIDTH=$OLD_WIDTH"
+
+RIGHT=$($INNER display-message -p -t "$FLOAT" '#{pane_right}')
+TOP=$($INNER display-message -p -t "$FLOAT" '#{pane_top}')
+X=$((RIGHT + 2))
+Y=$((TOP + 2))
+
+# Grab the right frame and enlarge the floating pane.
+mouse 0 "$X" "$Y" M
+mouse 32 "$((X + 1))" "$Y" M
+mouse 32 "$((X + 8))" "$Y" M
+mouse 0 "$((X + 8))" "$Y" m
+
+NEW_WIDTH=$($INNER display-message -p -t "$FLOAT" '#{pane_width}')
+[ "$NEW_WIDTH" -ne "$OLD_WIDTH" ] || fail "floating pane was not resized"
+wait_outer_has_status "WIDTH=$NEW_WIDTH"
+
+exit 0

regress/modal-pane.sh

@@ -337,9 +337,9 @@ $TMUX set -g @modal-prefix no
 $TMUX set -g @modal-root no
 $TMUX bind -n z set -g @modal-root yes
 
-modal=$($TMUX new-pane -ODKPF '#{pane_id}' -t "$p0" \
+modal=$($TMUX new-pane -OKPF '#{pane_id}' -t "$p0" \
     -x 20 -y 5 -X 20 -Y 10 'cat') ||
-	fail "new-pane -ODK failed"
+	fail "new-pane -OK failed"
 sleep 1
 $TMUX2 send-keys -t "$OUTER" C-b x z Enter
 sleep 1
@@ -356,50 +356,9 @@ new_left=$(fmt "$modal" '#{pane_left}')
 new_top=$(fmt "$modal" '#{pane_top}')
 [ "$new_left" -gt "$left" ] || [ "$new_top" -gt "$top" ] ||
 	fail "key-capturing modal pane did not move"
-$TMUX2 send-keys -t "$OUTER" Escape
-sleep 1
-must_equal "$(fmt modal:0 '#{window_modal_pane}')" ''
-
-modal=$($TMUX new-pane -ODKPF '#{pane_id}' -t "$p0" \
-    -x 20 -y 5 -X 20 -Y 10 'trap "" INT; exec cat') ||
-	fail "new-pane -ODK failed"
-sleep 1
-$TMUX2 send-keys -t "$OUTER" C-c
-sleep 1
-must_equal "$(fmt modal:0 '#{window_modal_pane}')" ''
-
-# A dead modal does not close on Escape or C-c without -D.
-modal=$($TMUX new-pane -OPF '#{pane_id}' -t "$p0" \
-    -x 20 -y 5 -X 20 -Y 10 'sleep 1') ||
-	fail "new-pane -O failed"
-check_ok set-option -p -t "$modal" remain-on-exit on
-sleep 2
-must_equal "$(fmt "$modal" '#{pane_dead}:#{pane_modal_flag}')" 1:1
-$TMUX2 send-keys -t "$OUTER" Escape
-sleep 1
-must_equal "$(fmt modal:0 '#{window_modal_pane}')" "$modal"
 check_ok kill-pane -t "$modal"
 sleep 1
 
-# failed-key closes successful panes and retains failed panes until a key.
-modal=$($TMUX new-pane -OPF '#{pane_id}' -t "$p0" \
-    -x 20 -y 5 -X 20 -Y 10 'sleep 1') ||
-	fail "new-pane -O failed"
-check_ok set-option -p -t "$modal" remain-on-exit failed-key
-sleep 2
-must_equal "$(fmt modal:0 '#{window_modal_pane}')" ''
-
-modal=$($TMUX new-pane -OPF '#{pane_id}' -t "$p0" \
-    -x 20 -y 5 -X 20 -Y 10 'sleep 1; exit 1') ||
-	fail "new-pane -O failed"
-check_ok set-option -p -t "$modal" remain-on-exit failed-key
-sleep 2
-must_equal "$(fmt "$modal" '#{pane_dead}:#{pane_modal_flag}')" 1:1
-must_equal "$($TMUX show-options -pv -t "$modal" remain-on-exit)" failed-key
-$TMUX2 send-keys -t "$OUTER" a
-sleep 1
-must_equal "$(fmt modal:0 '#{window_modal_pane}')" ''
-
 # A nonmodal floating pane may remain above zoom, and switching between it and
 # the zoomed tiled pane must not unzoom the window.
 check_ok new-window -d -t modal: -n float-over-zoom 'cat'

regress/options-values.sh

@@ -86,11 +86,6 @@ check_value "-gv status-keys" "vi"
 check_fail "unknown value: bogus" set -g status-keys bogus
 check_value "-gv status-keys" "vi"
 
-# pane-border-lines accepts rounded as a pane border style.
-check_ok set -gw pane-border-lines rounded
-check_value "-gwv pane-border-lines" "rounded"
-check_ok set -gw pane-border-lines single
-
 # --- flag options ---------------------------------------------------------
 #
 # focus-events is an on/off flag.  Setting with no value toggles it; explicit

regress/pane-ops.sh

@@ -104,25 +104,6 @@ assert_alive()
 	fi
 }
 
-# Compare layout geometry and pane ordering, ignoring the active pane and
-# last-pane history in the JSON layout. Selection is checked separately.
-pane_layout()
-{
-	$TMUX display-message -p -t "$1" '#{window_layout}' |
-		sed 's/,"a":true//g; s/,"l":[0-9][0-9]*//g'
-}
-
-check_layout()
-{
-	out=$(pane_layout "$1")
-	if [ "$out" != "$2" ]; then
-		echo "Layout for '$1' wrong."
-		echo "Expected: '$2'"
-		echo "But got:  '$out'"
-		exit 1
-	fi
-}
-
 # ---------------------------------------------------------------------------
 # split-window geometry.
 
@@ -328,12 +309,12 @@ check_ok kill-pane -t "$p6"
 
 # Zoom and unzoom preserve the exact tiled layout. Selecting another pane
 # without -Z unzooms, while -Z transfers zoom to the selected pane.
-layout=$(pane_layout P:0)
+layout=$($TMUX display-message -p -t P:0 '#{window_layout}')
 check_ok select-pane -t "$p0"
 check_ok resize-pane -Z -t "$p0"
 check_ok select-pane -t "$p2"
 check_fmt "$p2" '#{window_zoomed_flag}:#{pane_active}' '0:1'
-check_layout P:0 "$layout"
+check_fmt P:0 '#{window_layout}' "$layout"
 
 check_ok select-pane -t "$p0"
 check_ok resize-pane -Z -t "$p0"
@@ -341,7 +322,7 @@ check_ok select-pane -Z -t "$p2"
 check_fmt "$p2" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
 	'1:1:1'
 check_ok resize-pane -Z -t "$p2"
-check_layout P:0 "$layout"
+check_fmt P:0 '#{window_layout}' "$layout"
 
 # Directional selection temporarily restores the full layout to find its
 # neighbour, then follows the same unzoom or -Z transfer rules.
@@ -359,7 +340,7 @@ check_ok select-pane -D -Z -t "$p0"
 check_fmt "$p2" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
 	'1:1:1'
 check_ok resize-pane -Z -t "$p2"
-check_layout P:0 "$layout"
+check_fmt P:0 '#{window_layout}' "$layout"
 
 # The last-pane path has separate zoom handling, both with and without -Z.
 check_ok select-pane -t "$p0"
@@ -376,7 +357,7 @@ check_ok select-pane -l -Z -t P:0
 check_fmt "$p0" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
 	'1:1:1'
 check_ok resize-pane -Z -t "$p0"
-check_layout P:0 "$layout"
+check_fmt P:0 '#{window_layout}' "$layout"
 
 # Killing either a hidden ordinary pane or the zoom target unzooms.
 check_ok new-window -d -t P:12 -n zoom-kill 'cat'

regress/popup-drag-pane-prompt.sh

@@ -0,0 +1,97 @@
+#!/bin/sh
+
+# Moving a popup away from a pane prompt must recompose the prompt over the
+# pane contents restored by damage redraw.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+DIR=$(mktemp -d) || exit 1
+INNER="$TEST_TMUX -Lpopup-prompt-inner-$$ -f/dev/null"
+OUTER="$TEST_TMUX -Lpopup-prompt-outer-$$ -f/dev/null"
+CAPTURE=$DIR/capture
+POPUP_PID=
+
+fail()
+{
+	echo "$*" >&2
+	[ -s "$CAPTURE" ] && cat "$CAPTURE" >&2
+	exit 1
+}
+
+cleanup()
+{
+	[ -n "$POPUP_PID" ] && kill "$POPUP_PID" 2>/dev/null
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		CLIENT=$($INNER list-clients -F '#{client_name}' 2>/dev/null)
+		[ -n "$CLIENT" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner client did not attach"
+}
+
+wait_outer_has()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		grep -q "$marker" "$CAPTURE" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "outer client did not show $marker"
+}
+
+mouse()
+{
+	sequence=$(printf '\033[<%s;%s;%s%s' "$1" "$2" "$3" "$4")
+	$OUTER send-keys -t outer:0.0 -l "$sequence" || exit 1
+	sleep 0.1
+}
+
+C="sh -c 'i=1; while [ \$i -le 10 ]; do printf \"\\033[%d;1HAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\" \$i; i=\$((i + 1)); done; exec sleep 100'"
+
+$INNER new-session -d -s inner -x 40 -y 10 "$C" || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+$INNER set-option -g mouse on || exit 1
+
+$OUTER new-session -d -s outer -x 40 -y 10 'sleep 100' || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+$OUTER respawn-pane -k -t outer:0.0 \
+    "$TEST_TMUX -Lpopup-prompt-inner-$$ -f/dev/null attach-session -t inner" ||
+    exit 1
+
+wait_for_client
+$INNER command-prompt -b -P -t "$CLIENT" -p 'PROMPT-MARK>' \
+    'display-message -- %1' || exit 1
+wait_outer_has PROMPT-MARK
+
+$INNER display-popup -t "$CLIENT" -x 0 -y 10 -w 16 -h 3 -E \
+    "sh -c 'printf POPUP-MARKER; exec sleep 100'" &
+POPUP_PID=$!
+wait_outer_has POPUP-MARKER
+
+mouse 0 10 8 M
+mouse 32 11 8 M
+mouse 32 25 4 M
+mouse 0 25 4 m
+wait_outer_has PROMPT-MARK
+
+exit 0

regress/popup-drag-redraw.sh

@@ -0,0 +1,155 @@
+#!/bin/sh
+
+# Moving and resizing a popup must restore its old rectangle, including pane
+# border status, on the attached client's terminal.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+DIR=$(mktemp -d) || exit 1
+INNER="$TEST_TMUX -Lpopup-drag-inner-$$ -f/dev/null"
+OUTER="$TEST_TMUX -Lpopup-drag-outer-$$ -f/dev/null"
+BASE=$DIR/base
+CAPTURE=$DIR/capture
+RAW=$DIR/raw
+POPUP_PID=
+
+fail()
+{
+	echo "$*" >&2
+	[ -s "$CAPTURE" ] && cat "$CAPTURE" >&2
+	exit 1
+}
+
+cleanup()
+{
+	[ -n "$POPUP_PID" ] && kill "$POPUP_PID" 2>/dev/null
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		CLIENT=$($INNER list-clients -F '#{client_name}' 2>/dev/null)
+		[ -n "$CLIENT" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner client did not attach"
+}
+
+wait_outer_has()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		grep -q "$marker" "$CAPTURE" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "outer client did not show $marker"
+}
+
+wait_rows_match()
+{
+	first=$1
+	last=$2
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		sed -n "${first},${last}p" "$BASE" >"$DIR/want"
+		sed -n "${first},${last}p" "$CAPTURE" >"$DIR/got"
+		cmp -s "$DIR/want" "$DIR/got" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "outer rows $first-$last were not restored"
+}
+
+mouse()
+{
+	sequence=$(printf '\033[<%s;%s;%s%s' "$1" "$2" "$3" "$4")
+	$OUTER send-keys -t outer:0.0 -l "$sequence" || exit 1
+	sleep 0.1
+}
+
+# A left-button border drag moves the popup. The first motion starts the drag;
+# the second changes its position.
+move_popup()
+{
+	mouse 0 10 1 M
+	mouse 32 11 1 M
+	mouse 32 26 8 M
+	mouse 0 26 8 m
+}
+
+# A right-button bottom-right-border drag resizes the popup.
+resize_popup()
+{
+	mouse 2 "$1" "$2" M
+	mouse 34 "$3" "$4" M
+	mouse 34 "$5" "$6" M
+	mouse 2 "$5" "$6" m
+}
+
+C="sh -c 'i=0; while [ \$i -lt 20 ]; do printf \"\\033[%d;1HBG-ROW-%02d-abcdefghijklmnopqrstuvwxyz0123456789\" \$((i + 1)) \$i; i=\$((i + 1)); done; printf \"\\033[19;45H\\033[38;5;201mSCOPE\\033[0m\"; exec sleep 100'"
+
+$INNER new-session -d -s inner -x 60 -y 20 "$C" || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+$INNER set-option -g mouse on || exit 1
+$INNER set-option -w pane-border-status top || exit 1
+$INNER set-option -w pane-border-format 'DAMAGE-STATUS-RESTORED' || exit 1
+
+$OUTER new-session -d -s outer -x 60 -y 20 'sleep 100' || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+$OUTER set-option -g default-terminal screen-256color || exit 1
+$OUTER pipe-pane -O -t outer:0.0 "cat >'$RAW'" || exit 1
+$OUTER respawn-pane -k -t outer:0.0 \
+    "$TEST_TMUX -Lpopup-drag-inner-$$ -f/dev/null attach-session -t inner" ||
+    exit 1
+
+wait_for_client
+wait_outer_has SCOPE
+grep -qa '38;5;201' "$RAW" || fail "scope colour was not drawn initially"
+$OUTER capture-pane -p -t outer:0.0 >"$BASE" || exit 1
+grep -q DAMAGE-STATUS-RESTORED "$BASE" ||
+    fail "pane border status was not visible before popup"
+
+$INNER display-popup -t "$CLIENT" -x 0 -y 0 -w 28 -h 6 -E \
+    "sh -c 'printf POPUP-MARKER; exec sleep 100'" &
+POPUP_PID=$!
+wait_outer_has POPUP-MARKER
+$OUTER pipe-pane -t outer:0.0 || exit 1
+$OUTER pipe-pane -O -t outer:0.0 "cat >'$RAW'" || exit 1
+
+move_popup
+wait_rows_match 1 6
+$OUTER pipe-pane -t outer:0.0 || exit 1
+grep -qa '38;5;201' "$RAW" &&
+    fail "popup move redrew content outside its old and new rectangles"
+grep -q DAMAGE-STATUS-RESTORED "$CAPTURE" ||
+    fail "pane border status was not restored after popup move"
+
+# The moved popup is 28x6 at zero-based 16,7. Shrink it to 21x3, then require
+# the three rows vacated at the bottom to match the original scene.
+resize_popup 44 13 43 13 38 11
+wait_rows_match 11 13
+
+# Grow it back to 28x6 and require a single, intact popup frame.
+resize_popup 37 10 36 10 45 14
+wait_outer_has POPUP-MARKER
+corners=$(grep -o '┌' "$CAPTURE" | wc -l)
+[ "$corners" -eq 1 ] || fail "expected one popup frame, found $corners"
+
+exit 0

regress/popup-drag-status-line.sh

@@ -0,0 +1,165 @@
+#!/bin/sh
+
+# Moving a popup away from the tmux status area must restore status and window
+# cells. Window damage alone cannot describe cells outside the window scene,
+# and top status lines must be removed before translating to window rows.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+DIR=$(mktemp -d) || exit 1
+BASE=$DIR/base
+CAPTURE=$DIR/capture
+INNER=
+OUTER=
+POPUP_PID=
+N=0
+
+fail()
+{
+	echo "$*" >&2
+	[ -s "$CAPTURE" ] && cat "$CAPTURE" >&2
+	exit 1
+}
+
+cleanup_scene()
+{
+	[ -n "$POPUP_PID" ] && kill "$POPUP_PID" 2>/dev/null
+	[ -n "$OUTER" ] && $OUTER kill-server 2>/dev/null
+	[ -n "$INNER" ] && $INNER kill-server 2>/dev/null
+	POPUP_PID=
+}
+
+cleanup()
+{
+	cleanup_scene
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		CLIENT=$($INNER list-clients -F '#{client_name}' 2>/dev/null)
+		[ -n "$CLIENT" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner client did not attach"
+}
+
+wait_outer_has()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		grep -q "$marker" "$CAPTURE" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "outer client did not show $marker"
+}
+
+wait_rows_restored()
+{
+	first=$1
+	last=$2
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		sed -n "${first},${last}p" "$BASE" >"$DIR/want"
+		sed -n "${first},${last}p" "$CAPTURE" >"$DIR/got"
+		cmp -s "$DIR/want" "$DIR/got" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "rows $first-$last under the old popup were not restored"
+}
+
+mouse()
+{
+	sequence=$(printf '\033[<%s;%s;%s%s' "$1" "$2" "$3" "$4")
+	$OUTER send-keys -t outer:0.0 -l "$sequence" || exit 1
+	sleep 0.1
+}
+
+setup()
+{
+	position=$1
+	lines=$2
+
+	cleanup_scene
+	N=$((N + 1))
+	INNER="$TEST_TMUX -Lpopup-status-inner-$$-$N -f/dev/null"
+	OUTER="$TEST_TMUX -Lpopup-status-outer-$$-$N -f/dev/null"
+
+	C="sh -c 'i=1; while [ \$i -le 10 ]; do printf \"\\033[%d;1HAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\" \$i; i=\$((i + 1)); done; exec sleep 100'"
+	$INNER new-session -d -s inner -x 40 -y 10 "$C" || exit 1
+	$INNER set-option -g window-size manual || exit 1
+	$INNER set-option -g mouse on || exit 1
+	if [ "$lines" -eq 1 ]; then
+		$INNER set-option -g status on || exit 1
+	else
+		$INNER set-option -g status "$lines" || exit 1
+	fi
+	$INNER set-option -g status-position "$position" || exit 1
+	$INNER set-option -g status-format[0] \
+	    'STATUS-LINE-MARK-01234567890123456789012' || exit 1
+	if [ "$lines" -gt 1 ]; then
+		$INNER set-option -g status-format[1] \
+		    'SECOND-STATUS-MARK-012345678901234567890' || exit 1
+	fi
+	$INNER set-option -g status-interval 0 || exit 1
+
+	$OUTER new-session -d -s outer -x 40 -y 10 'sleep 100' || exit 1
+	$OUTER set-option -g status off || exit 1
+	$OUTER set-option -g window-size manual || exit 1
+	$OUTER respawn-pane -k -t outer:0.0 \
+	    "$TEST_TMUX -Lpopup-status-inner-$$-$N -f/dev/null attach-session -t inner" ||
+	    exit 1
+
+	wait_for_client
+	wait_outer_has STATUS-LINE-MARK
+	$OUTER capture-pane -p -t outer:0.0 >"$BASE" || exit 1
+}
+
+open_popup()
+{
+	y=$1
+	height=$2
+	$INNER display-popup -t "$CLIENT" -x 0 -y "$y" -w 16 -h "$height" -E \
+	    "sh -c 'printf POPUP-MARKER; exec sleep 100'" &
+	POPUP_PID=$!
+	wait_outer_has POPUP-MARKER
+}
+
+if [ "${STATUS_CASE:-all}" != top ]; then
+	# A popup clipped against a one-line bottom status must restore that line.
+	setup bottom 1
+	open_popup 10 3
+	mouse 0 10 8 M
+	mouse 32 11 8 M
+	mouse 32 25 4 M
+	mouse 0 25 4 m
+	wait_rows_restored 10 10
+fi
+
+if [ "${STATUS_CASE:-all}" != bottom ]; then
+	# A popup beginning in a two-line top status also covers the first window
+	# rows. Restore both coordinate spaces after it moves.
+	setup top 2
+	open_popup 1 4
+	mouse 0 10 1 M
+	mouse 32 11 1 M
+	mouse 32 25 7 M
+	mouse 0 25 7 m
+	wait_rows_restored 1 4
+fi
+
+exit 0

regress/popup-drag-wide-character.sh

@@ -0,0 +1,126 @@
+#!/bin/sh
+
+# Damage at a popup edge must redraw complete grid characters. Drawing only a
+# wide character's base or padding cell leaves a two-cell hole behind.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+DIR=$(mktemp -d) || exit 1
+INNER="$TEST_TMUX -Lpopup-wide-inner-$$ -f/dev/null"
+OUTER="$TEST_TMUX -Lpopup-wide-outer-$$ -f/dev/null"
+EMITTER=$DIR/emitter.pl
+BASE=$DIR/base
+CAPTURE=$DIR/capture
+POPUP_PID=
+
+fail()
+{
+	echo "$*" >&2
+	[ -s "$CAPTURE" ] && cat "$CAPTURE" >&2
+	exit 1
+}
+
+cleanup()
+{
+	[ -n "$POPUP_PID" ] && kill "$POPUP_PID" 2>/dev/null
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		CLIENT=$($INNER list-clients -F '#{client_name}' 2>/dev/null)
+		[ -n "$CLIENT" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner client did not attach"
+}
+
+wait_outer_has()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		grep -q "$marker" "$CAPTURE" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "outer client did not show $marker"
+}
+
+wait_old_rows_restored()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		sed -n '3,5p' "$BASE" >"$DIR/want"
+		sed -n '3,5p' "$CAPTURE" >"$DIR/got"
+		cmp -s "$DIR/want" "$DIR/got" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "wide characters under the old popup edge were not restored"
+}
+
+mouse()
+{
+	sequence=$(printf '\033[<%s;%s;%s%s' "$1" "$2" "$3" "$4")
+	$OUTER send-keys -t outer:0.0 -l "$sequence" || exit 1
+	sleep 0.1
+}
+
+cat >"$EMITTER" <<'PERL'
+use strict;
+use warnings;
+
+binmode STDOUT, ':encoding(UTF-8)';
+$| = 1;
+for my $row (1 .. 10) {
+	print "\e[$row;1H", chr(0x754c) x 20;
+}
+sleep 100;
+PERL
+
+$INNER new-session -d -s inner -x 40 -y 10 "perl '$EMITTER'" || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+$INNER set-option -g mouse on || exit 1
+
+$OUTER new-session -d -s outer -x 40 -y 10 'sleep 100' || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+$OUTER set-option -g default-terminal screen-256color || exit 1
+$OUTER respawn-pane -k -t outer:0.0 \
+    "$TEST_TMUX -Lpopup-wide-inner-$$ -f/dev/null attach-session -t inner" ||
+    exit 1
+
+wait_for_client
+wait_outer_has '界界界'
+$OUTER capture-pane -p -t outer:0.0 >"$BASE" || exit 1
+
+$INNER display-popup -t "$CLIENT" -x 5 -y 5 -w 10 -h 3 -E \
+    "sh -c 'printf POPUP; exec sleep 100'" &
+POPUP_PID=$!
+wait_outer_has POPUP
+
+# The first motion starts the drag; the second moves the popup away from its
+# old rectangle. Its odd x coordinate bisects the underlying double-width
+# cells at both edges.
+mouse 0 10 3 M
+mouse 32 11 3 M
+mouse 32 28 7 M
+mouse 0 28 7 m
+wait_old_rows_restored
+
+exit 0

regress/redraw-damage-only.sh

@@ -0,0 +1,112 @@
+#!/bin/sh
+
+# Check a redraw callback which has no accompanying client redraw flags. A
+# wrapped row crossing a panned viewport cannot use the direct tty path.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+DIR=$(mktemp -d) || exit 1
+INNER="$TEST_TMUX -Ldamage-only-inner-$$ -f/dev/null"
+OUTER="$TEST_TMUX -Ldamage-only-outer-$$ -f/dev/null"
+EMITTER=$DIR/emitter.pl
+TRIGGER=$DIR/trigger
+CAPTURE=$DIR/capture
+
+fail()
+{
+	echo "$*" >&2
+	[ -s "$CAPTURE" ] && cat "$CAPTURE" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		CLIENT=$($INNER list-clients -F '#{client_name}' 2>/dev/null)
+		[ -n "$CLIENT" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner client did not attach"
+}
+
+wait_outer_has()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		grep -q "$marker" "$CAPTURE" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "outer client did not show $marker"
+}
+
+wait_inner_has()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$INNER capture-pane -p -t inner:0.0 2>/dev/null |
+		    grep -q "$marker" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner pane did not contain $marker"
+}
+
+cat >"$EMITTER" <<'PERL'
+use strict;
+use warnings;
+
+$| = 1;
+for my $row (1 .. 12) {
+	print "\e[$row;1H", 'o' x 79;
+}
+print "\e[1;1H";
+while (!-e $ENV{TRIGGER}) {
+	select undef, undef, undef, 0.01;
+}
+
+my $second = ('B' x 24) . 'DAMAGE-ONLY' . ('B' x 45);
+print "\e[5;1H", ('A' x 80), $second;
+sleep 100;
+PERL
+
+$INNER new-session -d -s inner -x 80 -y 12 \
+    "TRIGGER='$TRIGGER' perl '$EMITTER'" || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+
+$OUTER new-session -d -s outer -x 40 -y 12 'sleep 100' || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+$OUTER set-option -g default-terminal screen || exit 1
+$OUTER respawn-pane -k -t outer:0.0 \
+    "$TEST_TMUX -Ldamage-only-inner-$$ -f/dev/null attach-session -t inner" ||
+    exit 1
+
+wait_for_client
+$INNER refresh-client -t "$CLIENT" -R 20 || exit 1
+wait_outer_has oooooooooo
+
+: >"$TRIGGER"
+wait_inner_has DAMAGE-ONLY
+wait_outer_has DAMAGE-ONLY
+
+exit 0

regress/redraw-multiclient.sh

@@ -0,0 +1,186 @@
+#!/bin/sh
+
+# Redraw a moved floating pane on both attached clients viewing the same
+# window. Window redraw work must not be consumed by only one client.
+#
+# Uses ASCII pane borders (rather than the default UTF-8 box-drawing) because
+# this test nests a real tmux client inside another tmux's pane to get a
+# genuine terminal to capture from; that nested-tmux relay has been observed
+# to mis-render a cell that previously held a multi-byte UTF-8 border
+# character being overwritten later by plain content, on the outer instance's
+# own interpretation, independent of anything the inner tmux sends. That is a
+# nested-test-harness artifact, not a real tmux bug - confirmed by replaying
+# the exact same drag sequence against a real terminal (xterm), where it
+# never reproduces. ASCII borders avoid the artifact entirely.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+DIR=$(mktemp -d) || exit 1
+INNER="$TEST_TMUX -Lredraw-multi-inner-$$ -f/dev/null"
+OUTER="$TEST_TMUX -Lredraw-multi-outer-$$ -f/dev/null"
+CAPTURE=$DIR/capture
+
+fail()
+{
+	echo "$*" >&2
+	[ -s "$CAPTURE" ] && cat "$CAPTURE" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_for_clients()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		count=$($INNER list-clients 2>/dev/null | wc -l)
+		[ "$count" -eq 2 ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "two inner clients did not attach"
+}
+
+wait_outer_has()
+{
+	target=$1
+	marker=$2
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t "$target" >"$CAPTURE" 2>/dev/null || true
+		grep -q "$marker" "$CAPTURE" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "outer pane $target did not show $marker"
+}
+
+wait_float_left()
+{
+	comparison=$1
+	limit=$2
+	i=0
+	while [ "$i" -lt 50 ]; do
+		left=$($INNER display-message -p -t "$FLOAT" '#{pane_left}')
+		if [ "$comparison" = gt ] && [ "$left" -gt "$limit" ]; then
+			return 0
+		fi
+		if [ "$comparison" = lt ] && [ "$left" -lt "$limit" ]; then
+			return 0
+		fi
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "floating pane did not move"
+}
+
+mouse()
+{
+	sequence=$(printf '\033[<%s;%s;%s%s' "$2" "$3" "$4" "$5")
+	$OUTER send-keys -t "$1" -l "$sequence" || exit 1
+	sleep 0.1
+}
+
+drag_float()
+{
+	target=$1
+	startcol=$2
+	startrow=$3
+	endcol=$4
+	mouse "$target" 0 "$startcol" "$startrow" M
+	mouse "$target" 32 "$endcol" "$startrow" M
+	mouse "$target" 0 "$endcol" "$startrow" m
+}
+
+assert_scene()
+{
+	target=$1
+	base=$2
+	firstcol=$3
+	lastcol=$4
+
+	$OUTER capture-pane -p -t "$target" >"$CAPTURE" || exit 1
+
+	# With ASCII (simple) borders every corner and junction is the same
+	# '+', so one rectangular floating pane always draws exactly 4 of
+	# them; more means a stale frame was left behind somewhere.
+	corners=$(grep -o '+' "$CAPTURE" | wc -l)
+	[ "$corners" -eq 4 ] ||
+	    fail "outer pane $target had $corners floating frames"
+
+	sed -n '6,11p' "$base" | cut -c"$firstcol-$lastcol" >"$DIR/want"
+	sed -n '6,11p' "$CAPTURE" | cut -c"$firstcol-$lastcol" >"$DIR/got"
+	cmp -s "$DIR/want" "$DIR/got" ||
+	    fail "outer pane $target did not restore the old floating area"
+}
+
+C="sh -c 'i=0; while [ \$i -lt 20 ]; do printf \"\\033[%d;1HBG-ROW-%02d-abcdefghijklmnopqrstuvwxyz0123456789\" \$((i + 1)) \$i; i=\$((i + 1)); done; exec sleep 100'"
+
+$INNER new-session -d -s inner -x 60 -y 20 "$C" || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+$INNER set-option -g mouse on || exit 1
+$INNER set-option -g default-command 'sleep 100' || exit 1
+$INNER set-option -g pane-border-lines simple || exit 1
+
+$OUTER new-session -d -s outer -x 121 -y 20 'sleep 100' || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+$OUTER set-option -g default-terminal screen || exit 1
+$OUTER split-window -h -t outer:0.0 'sleep 100' || exit 1
+
+PANES=$($OUTER list-panes -t outer:0 -F '#{pane_id} #{pane_left}')
+LEFT=$(echo "$PANES" | sort -k2 -n | head -1 | cut -d' ' -f1)
+RIGHT=$(echo "$PANES" | sort -k2 -n | tail -1 | cut -d' ' -f1)
+[ -n "$LEFT" ] && [ -n "$RIGHT" ] || fail "could not find outer panes"
+
+$OUTER respawn-pane -k -t "$LEFT" \
+    "$TEST_TMUX -Lredraw-multi-inner-$$ -f/dev/null attach-session -t inner" ||
+    exit 1
+$OUTER respawn-pane -k -t "$RIGHT" \
+    "$TEST_TMUX -Lredraw-multi-inner-$$ -f/dev/null attach-session -t inner" ||
+    exit 1
+
+wait_for_clients
+wait_outer_has "$LEFT" BG-ROW-19
+wait_outer_has "$RIGHT" BG-ROW-19
+$OUTER capture-pane -p -t "$LEFT" >"$DIR/base-left" || exit 1
+$OUTER capture-pane -p -t "$RIGHT" >"$DIR/base-right" || exit 1
+
+FLOAT=$($INNER new-pane -dPF '#{pane_id}' -x 16 -y 5 -X 5 -Y 5) ||
+    fail "could not create floating pane"
+wait_outer_has "$LEFT" '+'
+wait_outer_has "$RIGHT" '+'
+
+FTOP=$($INNER display-message -p -t "$FLOAT" '#{pane_top}')
+FLEFT=$($INNER display-message -p -t "$FLOAT" '#{pane_left}')
+FWIDTH=$($INNER display-message -p -t "$FLOAT" '#{pane_width}')
+GRABCOL=$((FLEFT + FWIDTH / 2 + 1))
+
+# Move right through one client and require both clients to restore the old
+# left-hand footprint.
+drag_float "$LEFT" "$GRABCOL" "$FTOP" $((GRABCOL + 30))
+wait_float_left gt 30
+assert_scene "$LEFT" "$DIR/base-left" 1 20
+assert_scene "$RIGHT" "$DIR/base-right" 1 20
+
+# Move back through the other client and check the old right-hand footprint.
+FLEFT=$($INNER display-message -p -t "$FLOAT" '#{pane_left}')
+GRABCOL=$((FLEFT + FWIDTH / 2 + 1))
+drag_float "$RIGHT" "$GRABCOL" "$FTOP" $((GRABCOL - 30))
+wait_float_left lt 10
+assert_scene "$LEFT" "$DIR/base-left" 35 60
+assert_scene "$RIGHT" "$DIR/base-right" 35 60
+
+exit 0

regress/redraw-screen-write.sh

@@ -0,0 +1,208 @@
+#!/bin/sh
+
+# Check that full and region screen-write fallbacks update an attached client,
+# not only tmux's internal pane grid.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+DIR=$(mktemp -d) || exit 1
+EMITTER=$DIR/emitter.pl
+CAPTURE=$DIR/capture
+INNER=
+OUTER=
+N=0
+
+fail()
+{
+	echo "$*" >&2
+	[ -s "$CAPTURE" ] && cat "$CAPTURE" >&2
+	exit 1
+}
+
+cleanup()
+{
+	[ -n "$OUTER" ] && $OUTER kill-server 2>/dev/null
+	[ -n "$INNER" ] && $INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_outer_has()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		grep -q "$marker" "$CAPTURE" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "outer client did not show $marker"
+}
+
+wait_outer_lacks()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		grep -q "$marker" "$CAPTURE" || return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "outer client still showed $marker"
+}
+
+wait_inner_has()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$INNER capture-pane -p -t inner:0.0 2>/dev/null |
+		    grep -q "$marker" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner pane did not contain $marker"
+}
+
+wait_inner_lacks()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$INNER capture-pane -p -t inner:0.0 >"$CAPTURE" 2>/dev/null || true
+		grep -q "$marker" "$CAPTURE" || return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner pane still contained $marker"
+}
+
+setup()
+{
+	mode=$1
+	[ -n "$OUTER" ] && $OUTER kill-server 2>/dev/null
+	[ -n "$INNER" ] && $INNER kill-server 2>/dev/null
+	N=$((N + 1))
+	INNER="$TEST_TMUX -Lredraw-write-inner-$$-$N -f/dev/null"
+	OUTER="$TEST_TMUX -Lredraw-write-outer-$$-$N -f/dev/null"
+
+	$INNER new-session -d -s inner -x 40 -y 12 \
+	    "MODE=$mode READY='$DIR/ready-$N' TRIGGER='$DIR/trigger-$N' perl '$EMITTER'" ||
+	    exit 1
+	$INNER set-option -g status off || exit 1
+	$INNER set-option -g window-size manual || exit 1
+
+	$OUTER new-session -d -s outer -x 40 -y 12 'sleep 100' || exit 1
+	$OUTER set-option -g status off || exit 1
+	$OUTER set-option -g window-size manual || exit 1
+	$OUTER set-option -g default-terminal screen || exit 1
+	$OUTER respawn-pane -k -t outer:0.0 \
+	    "$TEST_TMUX -Lredraw-write-inner-$$-$N -f/dev/null attach-session -t inner" ||
+	    exit 1
+}
+
+trigger()
+{
+	: >"$DIR/trigger-$N-${1:-1}"
+}
+
+cat >"$EMITTER" <<'PERL'
+use strict;
+use warnings;
+
+$| = 1;
+my $mode = $ENV{MODE};
+my $ready = $ENV{READY};
+my $trigger = $ENV{TRIGGER};
+
+sub fill_screen {
+	my ($prefix) = @_;
+	print "\e[2J\e[H";
+	for my $row (0 .. 11) {
+		printf "\e[%d;1H%s-ROW-%02d", $row + 1, $prefix, $row;
+	}
+}
+
+if ($mode eq 'ris') {
+	fill_screen('RIS');
+} elsif ($mode eq 'alternate') {
+	fill_screen('BASE');
+} elsif ($mode eq 'scroll') {
+	fill_screen('SCROLL');
+} else {
+	die "unknown mode $mode\n";
+}
+
+open my $fh, '>', $ready or die "$ready: $!\n";
+close $fh;
+while (!-e "$trigger-1") {
+	select undef, undef, undef, 0.01;
+}
+
+if ($mode eq 'ris') {
+	print "\ec";
+} elsif ($mode eq 'alternate') {
+	print "\e[?1049h";
+	fill_screen('ALT');
+	while (!-e "$trigger-2") {
+		select undef, undef, undef, 0.01;
+	}
+	print "\e[?1049l";
+} else {
+	print "\e[12;1H\r\nSCROLL-NEW";
+}
+sleep 100;
+PERL
+
+# RIS clears the complete screen. The source pane and attached client must both
+# lose every old row.
+setup ris
+wait_outer_has RIS-ROW-11
+trigger
+wait_inner_lacks RIS-ROW
+wait_outer_lacks RIS-ROW
+
+# Leaving the alternate screen restores every row of the base screen.
+setup alternate
+wait_outer_has BASE-ROW-11
+trigger
+wait_inner_has ALT-ROW-11
+wait_outer_has ALT-ROW-11
+wait_outer_lacks BASE-ROW
+trigger 2
+wait_inner_has BASE-ROW-11
+wait_outer_has BASE-ROW-11
+wait_outer_lacks ALT-ROW
+
+# Scrolling a pane which is narrower than the terminal redraws its complete
+# region. Check the physical client row by row after the source grid shifts.
+setup scroll
+$INNER split-window -h -t inner:0 'sleep 100' || exit 1
+wait_outer_has SCROLL-ROW-11
+trigger
+wait_inner_has SCROLL-NEW
+wait_outer_has SCROLL-NEW
+row=1
+while [ "$row" -le 11 ]; do
+	expected=$(printf 'SCROLL-ROW-%02d' "$row")
+	actual=$(sed -n "${row}p" "$CAPTURE")
+	case "$actual" in
+	"$expected"*) ;;
+	*) fail "outer row $row was not redrawn as $expected" ;;
+	esac
+	row=$((row + 1))
+done
+actual=$(sed -n '12p' "$CAPTURE")
+case "$actual" in
+SCROLL-NEW*) ;;
+*) fail "outer bottom row was not redrawn as SCROLL-NEW" ;;
+esac
+
+exit 0

regress/screen-redraw-floating.sh

@@ -107,12 +107,6 @@ $TMUX2 new-pane -x28 -y8 -X4 -Y1 -B double \
 	"sh -c 'printf FLOAT; exec sleep 100'" || exit 1
 compare floating-border-double
 
-# Larger floating pane with rounded border lines.
-new_scene 40 12
-$TMUX2 new-pane -x28 -y8 -X4 -Y1 -B rounded \
-	"sh -c 'printf FLOAT; exec sleep 100'" || exit 1
-compare floating-border-rounded
-
 # Floating pane with no border lines: redraw_mark_pane_borders returns early so
 # the float has no border at all, only its (clipped) content over the base pane.
 new_scene 40 12

regress/screen-redraw-results/floating-border-rounded.result

@@ -1,12 +0,0 @@
-base
-    ╭──────────────────────────╮
-    │FLOAT                     │
-    │                          │
-    │                          │
-    │                          │
-    │                          │
-    │                          │
-    ╰──────────────────────────╯
-
-
-

regress/switch-client-redraw.sh

@@ -0,0 +1,81 @@
+#!/bin/sh
+
+# Switching windows in the same session must redraw the attached client. The
+# session object is shared, so its current winlink cannot be compared after it
+# has already been changed.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export PATH TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+DIR=$(mktemp -d) || exit 1
+INNER="$TEST_TMUX -Lswitch-redraw-inner-$$ -f/dev/null"
+OUTER="$TEST_TMUX -Lswitch-redraw-outer-$$ -f/dev/null"
+CAPTURE=$DIR/capture
+
+fail()
+{
+	echo "$*" >&2
+	[ -s "$CAPTURE" ] && cat "$CAPTURE" >&2
+	exit 1
+}
+
+cleanup()
+{
+	$OUTER kill-server 2>/dev/null
+	$INNER kill-server 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+wait_for_client()
+{
+	i=0
+	while [ "$i" -lt 50 ]; do
+		CLIENT=$($INNER list-clients -F '#{client_name}' 2>/dev/null)
+		[ -n "$CLIENT" ] && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "inner client did not attach"
+}
+
+wait_outer_has()
+{
+	marker=$1
+	i=0
+	while [ "$i" -lt 50 ]; do
+		$OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true
+		grep -q "$marker" "$CAPTURE" && return 0
+		sleep 0.1
+		i=$((i + 1))
+	done
+	fail "outer client did not show $marker"
+}
+
+$INNER new-session -d -s inner -x 40 -y 8 \
+    "printf '\033[2J\033[HA-WINDOW'; exec sleep 100" || exit 1
+$INNER new-window -d -t inner:1 \
+    "printf '\033[2J\033[HB-WINDOW'; exec sleep 100" || exit 1
+$INNER set-option -g status off || exit 1
+$INNER set-option -g window-size manual || exit 1
+
+$OUTER new-session -d -s outer -x 40 -y 8 'sleep 100' || exit 1
+$OUTER set-option -g status off || exit 1
+$OUTER set-option -g window-size manual || exit 1
+$OUTER respawn-pane -k -t outer:0.0 \
+    "$TEST_TMUX -Lswitch-redraw-inner-$$ -f/dev/null attach-session -t inner:0" ||
+    exit 1
+
+wait_for_client
+wait_outer_has A-WINDOW
+
+$INNER switch-client -c "$CLIENT" -t inner:1.0 || exit 1
+[ "$($INNER display-message -p -t inner '#{window_index}')" -eq 1 ] ||
+    fail "server did not select window 1"
+wait_outer_has B-WINDOW
+
+exit 0

screen-redraw.c

@@ -205,6 +205,22 @@ struct redraw_scene {
 	u_int			 oy;
 };
 
+/* A single damaged window-coordinate rectangle. */
+struct redraw_damage {
+	u_int			 x;
+	u_int			 y;
+	u_int			 sx;
+	u_int			 sy;
+
+	TAILQ_ENTRY(redraw_damage) entry;
+};
+
+/*
+ * Cap on the number of pending damage rectangles per window before they are
+ * collapsed into a single rectangle covering their union.
+ */
+#define REDRAW_DAMAGE_MAX 16
+
 /* Cell for building the scene. */
 struct redraw_build_cell {
 	struct redraw_span_data	 data;
@@ -1057,6 +1073,13 @@ redraw_free_scene(struct redraw_scene *scene)
 	free(scene);
 }
 
+/* Does a client's cached scene show this window? */
+int
+redraw_client_has_window(struct client *c, struct window *w)
+{
+	return (c->redraw_scene != NULL && c->redraw_scene->w == w);
+}
+
 /* Mark a window's cached redraw scenes as out of date. */
 void
 redraw_invalidate_scene(struct window *w)
@@ -1064,6 +1087,114 @@ redraw_invalidate_scene(struct window *w)
 	w->redraw_scene_generation++;
 }
 
+/* Free all pending damage for a window. */
+void
+redraw_free_damage(struct window *w)
+{
+	struct redraw_damage	*rd, *rd1;
+
+	TAILQ_FOREACH_SAFE(rd, &w->damage, entry, rd1) {
+		TAILQ_REMOVE(&w->damage, rd, entry);
+		free(rd);
+	}
+	w->damage_count = 0;
+}
+
+/* Collapse all pending damage for a window into one rectangle - its union. */
+static void
+redraw_collapse_damage(struct window *w)
+{
+	struct redraw_damage	*rd, *rd1, *first;
+	u_int			 x0, y0, x1, y1;
+
+	first = TAILQ_FIRST(&w->damage);
+	if (first == NULL)
+		return;
+	x0 = first->x;
+	y0 = first->y;
+	x1 = first->x + first->sx;
+	y1 = first->y + first->sy;
+
+	TAILQ_FOREACH_SAFE(rd, &w->damage, entry, rd1) {
+		if (rd->x < x0)
+			x0 = rd->x;
+		if (rd->y < y0)
+			y0 = rd->y;
+		if (rd->x + rd->sx > x1)
+			x1 = rd->x + rd->sx;
+		if (rd->y + rd->sy > y1)
+			y1 = rd->y + rd->sy;
+		if (rd != first) {
+			TAILQ_REMOVE(&w->damage, rd, entry);
+			free(rd);
+		}
+	}
+
+	first->x = x0;
+	first->y = y0;
+	first->sx = x1 - x0;
+	first->sy = y1 - y0;
+	w->damage_count = 1;
+}
+
+/*
+ * Record a damaged window-coordinate rectangle. Clips it to the window,
+ * merges it with an existing rectangle where doing so does not make the
+ * result substantially larger than the two combined, and collapses the
+ * whole list to its union once it grows past a modest cap.
+ *
+ * This only records damage - nothing consumes it yet.
+ */
+void
+redraw_damage_window(struct window *w, u_int x, u_int y, u_int sx, u_int sy)
+{
+	struct redraw_damage	*rd;
+	u_int			 x0, y0, x1, y1, area, union_area;
+
+	if (x >= w->sx || y >= w->sy)
+		return;
+	if (x + sx > w->sx)
+		sx = w->sx - x;
+	if (y + sy > w->sy)
+		sy = w->sy - y;
+	if (sx == 0 || sy == 0)
+		return;
+
+	TAILQ_FOREACH(rd, &w->damage, entry) {
+		/* Skip unless overlapping or directly adjacent. */
+		if (x > rd->x + rd->sx || rd->x > x + sx ||
+		    y > rd->y + rd->sy || rd->y > y + sy)
+			continue;
+
+		x0 = (x < rd->x) ? x : rd->x;
+		y0 = (y < rd->y) ? y : rd->y;
+		x1 = (x + sx > rd->x + rd->sx) ? x + sx : rd->x + rd->sx;
+		y1 = (y + sy > rd->y + rd->sy) ? y + sy : rd->y + rd->sy;
+
+		area = sx * sy + rd->sx * rd->sy;
+		union_area = (x1 - x0) * (y1 - y0);
+		if (union_area > 2 * area)
+			continue;
+
+		rd->x = x0;
+		rd->y = y0;
+		rd->sx = x1 - x0;
+		rd->sy = y1 - y0;
+		return;
+	}
+
+	rd = xcalloc(1, sizeof *rd);
+	rd->x = x;
+	rd->y = y;
+	rd->sx = sx;
+	rd->sy = sy;
+	TAILQ_INSERT_TAIL(&w->damage, rd, entry);
+	w->damage_count++;
+
+	if (w->damage_count > REDRAW_DAMAGE_MAX)
+		redraw_collapse_damage(w);
+}
+
 /* Mark all cached redraw scenes as out of date. */
 void
 redraw_invalidate_all_scenes(void)
@@ -1376,10 +1507,15 @@ redraw_draw_menu_span(struct redraw_draw_ctx *dctx,
 	tty_draw_line(tty, s, px, span->data.m.py, n, x, y, NULL);
 }
 
-/* Draw a span. */
+/*
+ * Draw a span, restricted to [clip_x, clip_x + clip_n) - a caller drawing
+ * the whole span passes the span's own x/width here; a caller drawing only
+ * a damaged sub-range passes that range instead. Overlay clipping (menus,
+ * popups) is then applied on top of this, exactly as before.
+ */
 static void
 redraw_draw_span(struct redraw_draw_ctx *dctx, struct redraw_span *span,
-    u_int y)
+    u_int y, u_int clip_x, u_int clip_n)
 {
 	struct redraw_scene	*scene = dctx->scene;
 	struct redraw_span_data	*data = &span->data;
@@ -1393,7 +1529,7 @@ redraw_draw_span(struct redraw_draw_ctx *dctx, struct redraw_span *span,
 	if (type == REDRAW_SPAN_STATUS && ~data->st.wp->flags & PANE_NEWSTATUS)
 		return;
 
-	r = tty_check_overlay_range(tty, span->x, y, span->width);
+	r = tty_check_overlay_range(tty, clip_x, y, clip_n);
 	for (i = 0; i < r->used; i++) {
 		rr = &r->ranges[i];
 		if (rr->nx == 0)
@@ -1453,15 +1589,19 @@ redraw_draw_pane_lines(struct redraw_draw_ctx *dctx, struct window_pane *wp,
 		if (flags & REDRAW_PANE) {
 			spans = &line->spans[REDRAW_SPAN_PANE];
 			TAILQ_FOREACH(span, spans, entry) {
-				if (span->data.p.wp == wp)
+				if (span->data.p.wp == wp) {
-					redraw_draw_span(dctx, span, cy);
+					redraw_draw_span(dctx, span, cy,
+					    span->x, span->width);
+				}
 			}
 		}
 		if (flags & REDRAW_PANE_SCROLLBAR) {
 			spans = &line->spans[REDRAW_SPAN_SCROLLBAR];
 			TAILQ_FOREACH(span, spans, entry) {
-				if (span->data.sb.wp == wp)
+				if (span->data.sb.wp == wp) {
-					redraw_draw_span(dctx, span, cy);
+					redraw_draw_span(dctx, span, cy,
+					    span->x, span->width);
+				}
 			}
 		}
 	}
@@ -1519,8 +1659,10 @@ redraw_draw_lines(struct redraw_draw_ctx *dctx, int flags)
 				}
 			}
 			spans = &line->spans[type];
-			TAILQ_FOREACH(span, spans, entry)
+			TAILQ_FOREACH(span, spans, entry) {
-				redraw_draw_span(dctx, span, cy);
+				redraw_draw_span(dctx, span, cy, span->x,
+				    span->width);
+			}
 		}
 	}
 }
@@ -1540,8 +1682,10 @@ redraw_draw_menu_lines(struct redraw_draw_ctx *dctx)
 			cy = dctx->status_lines + y;
 		else
 			cy = y;
-		TAILQ_FOREACH(span, &line->spans[REDRAW_SPAN_MENU], entry)
+		TAILQ_FOREACH(span, &line->spans[REDRAW_SPAN_MENU], entry) {
-			redraw_draw_span(dctx, span, cy);
+			redraw_draw_span(dctx, span, cy, span->x,
+			    span->width);
+		}
 	}
 }
 
@@ -1621,6 +1765,24 @@ redraw_set_draw_context(struct redraw_draw_ctx *dctx,
 		dctx->flags |= REDRAW_ISOLATES;
 }
 
+/* Build a pane prompt into a one-line screen. */
+static void
+redraw_make_pane_prompt(struct window_pane *wp, struct screen *screen)
+{
+	struct screen_write_ctx	 ctx;
+	struct prompt_draw_data	 pdd;
+
+	screen_init(screen, wp->sx, 1, 0);
+	screen_write_start(&ctx, screen);
+	pdd.ctx = &ctx;
+	pdd.cursor_x = &wp->prompt_cx;
+	pdd.area_x = 0;
+	pdd.area_width = wp->sx;
+	pdd.prompt_line = 0;
+	prompt_draw(wp->prompt, &pdd);
+	screen_write_stop(&ctx);
+}
+
 /* Draw a pane's prompt over its content. */
 static void
 redraw_draw_pane_prompt(struct redraw_draw_ctx *dctx, struct window_pane *wp)
@@ -1629,8 +1791,6 @@ redraw_draw_pane_prompt(struct redraw_draw_ctx *dctx, struct window_pane *wp)
 	struct client		*c = scene->c;
 	struct tty		*tty = &c->tty;
 	struct screen		 screen;
-	struct screen_write_ctx	 ctx;
-	struct prompt_draw_data	 pdd;
 	int			 ox = scene->ox, oy = scene->oy;
 	int			 sx = scene->sx, sy = scene->sy;
 	int			 line, cy, px, offset, width, wy;
@@ -1663,16 +1823,7 @@ redraw_draw_pane_prompt(struct redraw_draw_ctx *dctx, struct window_pane *wp)
 	if (px + width > sx)
 		width = sx - px;
 
-	screen_init(&screen, wp->sx, 1, 0);
+	redraw_make_pane_prompt(wp, &screen);
-	screen_write_start(&ctx, &screen);
-	pdd.ctx = &ctx;
-	pdd.cursor_x = &wp->prompt_cx;
-	pdd.area_x = 0;
-	pdd.area_width = wp->sx;
-	pdd.prompt_line = 0;
-	prompt_draw(wp->prompt, &pdd);
-	screen_write_stop(&ctx);
-
 	tty_draw_line(tty, &screen, 0, offset, width, px, cy, NULL);
 	screen_free(&screen);
 }
@@ -1704,7 +1855,8 @@ redraw_draw(struct client *c, struct window_pane *wp, int flags)
 			redraw = status_prompt_redraw(c);
 		else
 			redraw = status_redraw(c);
-		if (!redraw && !REDRAW_IS_ALL(flags)) {
+		if (!redraw && (~c->flags & CLIENT_REDRAWSTATUSALWAYS) &&
+		    !REDRAW_IS_ALL(flags)) {
 			flags &= ~REDRAW_STATUS;
 			if (flags == 0)
 				return;
@@ -1875,7 +2027,7 @@ redraw_screen(struct client *c)
 	} else {
 		if (c->flags & CLIENT_REDRAWBORDERS)
 			flags |= (REDRAW_PANE_BORDER|REDRAW_PANE_STATUS);
-		if (c->flags & CLIENT_REDRAWSTATUS)
+		if (c->flags & (CLIENT_REDRAWSTATUS|CLIENT_REDRAWSTATUSALWAYS))
 			flags |= (REDRAW_STATUS|REDRAW_PANE_STATUS);
 		if (c->flags & CLIENT_REDRAWOVERLAY)
 			flags |= REDRAW_OVERLAY;
@@ -1903,3 +2055,190 @@ redraw_pane_scrollbar(struct client *c, struct window_pane *wp)
 {
 	redraw_draw(c, wp, REDRAW_PANE_SCROLLBAR);
 }
+
+/*
+ * A REDRAW_SPAN_STATUS span within a damaged rectangle needs its content
+ * rebuilt and force-drawn regardless of whether that content has logically
+ * changed. window_make_pane_status()'s grid_compare() only tells us
+ * whether the *content* changed, not whether the physical cells were
+ * disturbed by something else (e.g. a floating pane sliding across this
+ * row) - and being inside a damage rectangle already proves that happened.
+ * Without this, redraw_draw_span() silently skips REDRAW_SPAN_STATUS spans
+ * whenever PANE_NEWSTATUS is not set, leaving a pane's border-status title
+ * blank until some unrelated redraw happens to touch it (e.g. a focus
+ * change or window resize).
+ */
+static void
+redraw_damage_refresh_status(struct redraw_draw_ctx *dctx,
+    struct window_pane *wp)
+{
+	struct redraw_span	*first;
+	u_int			 width;
+
+	if (wp->flags & PANE_NEWSTATUS)
+		return;
+	width = redraw_pane_status_width(dctx, wp, &first);
+	if (width == 0)
+		return;
+	window_make_pane_status(wp, dctx->scene->c, width, first);
+	wp->flags |= PANE_NEWSTATUS;
+}
+
+/*
+ * Grow a clipped span range by one cell on either edge that isn't already at
+ * the span's own boundary. A clip edge that lands mid-character (this is a
+ * damage rectangle, so its edges are geometric and have no idea what's in
+ * the grid) may be sitting on the second, padding half of a wide character
+ * whose first half falls just outside the requested range - growing by one
+ * cell is always enough to pull the whole character back in, since no grid
+ * cell is ever wider than two columns, and clamping to the span's own x and
+ * width keeps this from bleeding into a neighbouring span.
+ */
+static void
+redraw_damage_grow_span_clip(struct redraw_span *span, u_int *xp, u_int *endp)
+{
+	if (*xp > span->x)
+		(*xp)--;
+	if (*endp < span->x + span->width)
+		(*endp)++;
+}
+
+/* Recompose a pane's prompt over a damaged section of its display row. */
+static void
+redraw_damage_draw_pane_prompt(struct redraw_draw_ctx *dctx,
+    struct redraw_span *span, u_int y, u_int x, u_int n)
+{
+	struct redraw_scene	*scene = dctx->scene;
+	struct window_pane	*wp = span->data.p.wp;
+	struct tty		*tty = &scene->c->tty;
+	struct visible_ranges	*r;
+	struct visible_range	*rr;
+	struct screen		 screen;
+	u_int			 i, px, width, prompt_y;
+
+	if (wp->prompt == NULL || wp->sx == 0 || wp->sy == 0)
+		return;
+	if (dctx->flags & REDRAW_STATUS_TOP)
+		prompt_y = 0;
+	else
+		prompt_y = wp->sy - 1;
+	if (span->data.p.py != prompt_y)
+		return;
+
+	redraw_make_pane_prompt(wp, &screen);
+	r = tty_check_overlay_range(tty, x, y, n);
+	for (i = 0; i < r->used; i++) {
+		rr = &r->ranges[i];
+		if (rr->nx == 0)
+			continue;
+		px = span->data.p.px + (rr->px - span->x);
+		if (px >= screen_size_x(&screen))
+			continue;
+		width = rr->nx;
+		if (width > screen_size_x(&screen) - px)
+			width = screen_size_x(&screen) - px;
+		tty_draw_line(tty, &screen, px, 0, width, rr->px, y, NULL);
+	}
+	screen_free(&screen);
+}
+
+/*
+ * Compose exactly the cells within a damaged rectangle (already in this
+ * client's own scene coordinates), rather than a whole pane. For each row
+ * in range, every span of every type whose x-range intersects the
+ * rectangle is drawn restricted to just the intersected sub-range.
+ */
+static void
+redraw_draw_damage_rect(struct redraw_draw_ctx *dctx, u_int x, u_int y,
+    u_int sx, u_int sy)
+{
+	struct redraw_scene	*scene = dctx->scene;
+	struct redraw_line	*line;
+	struct redraw_spans	*spans;
+	struct redraw_span	*span;
+	u_int			 cy, yy, clip_x, clip_end, type;
+
+	if (x >= scene->sx || y >= scene->sy)
+		return;
+	if (x + sx > scene->sx)
+		sx = scene->sx - x;
+	if (y + sy > scene->sy)
+		sy = scene->sy - y;
+	if (sx == 0 || sy == 0)
+		return;
+
+	for (yy = y; yy < y + sy; yy++) {
+		line = &scene->lines[yy];
+		if (dctx->flags & REDRAW_STATUS_TOP)
+			cy = dctx->status_lines + yy;
+		else
+			cy = yy;
+		for (type = 0; type < REDRAW_SPAN_TYPES; type++) {
+			spans = &line->spans[type];
+			TAILQ_FOREACH(span, spans, entry) {
+				clip_x = (span->x > x) ? span->x : x;
+				clip_end = (span->x + span->width < x + sx) ?
+				    span->x + span->width : x + sx;
+				if (clip_end <= clip_x)
+					continue;
+				if (type == REDRAW_SPAN_STATUS) {
+					redraw_damage_refresh_status(dctx,
+					    span->data.st.wp);
+				}
+				redraw_damage_grow_span_clip(span, &clip_x,
+				    &clip_end);
+				redraw_draw_span(dctx, span, cy, clip_x,
+				    clip_end - clip_x);
+				if (type == REDRAW_SPAN_PANE) {
+					redraw_damage_draw_pane_prompt(dctx,
+					    span, cy, clip_x,
+					    clip_end - clip_x);
+				}
+			}
+		}
+	}
+}
+
+/*
+ * Consume a client's window's pending damage by composing exactly the
+ * damaged cells, after clipping each rectangle to what this client can see
+ * and translating it into this client's own scene coordinates.
+ *
+ * Unlike redraw_pane(), this does not redraw a whole pane's worth of cells
+ * for a small disturbance - only the cells within the (clipped) rectangle
+ * are touched, via redraw_draw_damage_rect().
+ */
+void
+redraw_client_damage(struct client *c)
+{
+	struct window		*w = c->session->curw->window;
+	struct redraw_scene	*scene;
+	struct redraw_draw_ctx	 dctx;
+	struct redraw_damage	*rd;
+	u_int			 ox, oy, sx, sy, x0, y0, x1, y1;
+
+	if (TAILQ_EMPTY(&w->damage))
+		return;
+
+	scene = redraw_get_scene(c);
+	if (scene == NULL)
+		return;
+	redraw_set_draw_context(&dctx, scene);
+	redraw_get_window_offset(c, &ox, &oy, &sx, &sy);
+
+	tty_sync_start(&c->tty);
+	tty_update_mode(&c->tty, c->tty.mode & ~CURSOR_MODES, NULL);
+
+	TAILQ_FOREACH(rd, &w->damage, entry) {
+		x0 = (rd->x > ox) ? rd->x : ox;
+		y0 = (rd->y > oy) ? rd->y : oy;
+		x1 = (rd->x + rd->sx < ox + sx) ? rd->x + rd->sx : ox + sx;
+		y1 = (rd->y + rd->sy < oy + sy) ? rd->y + rd->sy : oy + sy;
+		if (x0 >= x1 || y0 >= y1)
+			continue;
+		log_debug("%s: %s composing damage %u,%u %ux%u", __func__,
+		    c->name, x0 - ox, y0 - oy, x1 - x0, y1 - y0);
+		redraw_draw_damage_rect(&dctx, x0 - ox, y0 - oy, x1 - x0,
+		    y1 - y0);
+	}
+}

screen-write.c

@@ -120,14 +120,20 @@ screen_write_set_cursor(struct screen_write_ctx *ctx, int cx, int cy)
 		evtimer_add(&w->offset_timer, &tv);
 }
 
-/* Do a full redraw. */
+/*
+ * Called when a write could not be applied directly to the terminal and
+ * needs a redraw instead. Report damage for the requested rows. wp->yoff is
+ * already adjusted past any top pane-border-status row, so wp->yoff + py is
+ * the correct window-coordinate row.
+ */
 static void
-screen_write_redraw_cb(const struct tty_ctx *ttyctx)
+screen_write_redraw_cb(const struct tty_ctx *ttyctx, u_int py, u_int ny)
 {
 	struct window_pane	*wp = ttyctx->arg;
 
-	if (wp != NULL)
+	if (wp == NULL)
-		wp->flags |= PANE_REDRAW;
+		return;
+	redraw_damage_window(wp->window, wp->xoff, wp->yoff + py, wp->sx, ny);
 }
 
 /* Update context for client. */
@@ -2155,7 +2161,7 @@ screen_write_fullredraw(struct screen_write_ctx *ctx)
 
 	screen_write_initctx(ctx, &ttyctx, 1, 0);
 	if (ttyctx.redraw_cb != NULL)
-		ttyctx.redraw_cb(&ttyctx);
+		ttyctx.redraw_cb(&ttyctx, 0, ttyctx.sy);
 }
 
 /* Trim collected items. */
@@ -3175,7 +3181,7 @@ screen_write_alternateon(struct screen_write_ctx *ctx, struct grid_cell *gc,
 
 	screen_write_initctx(ctx, &ttyctx, 1, 0);
 	if (ttyctx.redraw_cb != NULL)
-		ttyctx.redraw_cb(&ttyctx);
+		ttyctx.redraw_cb(&ttyctx, 0, ttyctx.sy);
 }
 
 /* Turn alternate screen off. */
@@ -3200,5 +3206,5 @@ screen_write_alternateoff(struct screen_write_ctx *ctx, struct grid_cell *gc,
 
 	screen_write_initctx(ctx, &ttyctx, 1, 0);
 	if (ttyctx.redraw_cb != NULL)
-		ttyctx.redraw_cb(&ttyctx);
+		ttyctx.redraw_cb(&ttyctx, 0, ttyctx.sy);
 }

server-client.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: server-client.c,v 1.512 2026/09/10 11:02:18 nicm Exp $ */
+/* $OpenBSD: server-client.c,v 1.511 2026/09/08 10:20:08 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -473,7 +473,33 @@ server_client_set_session(struct client *c, struct session *s)
 		tty_update_client_offset(c);
 		status_timer_start(c);
 		server_client_fire_session_changed(c, old);
-		server_redraw_client(c);
+
+		/*
+		 * A full redraw is only needed if the client's session or
+		 * current window actually changed - not if this merely
+		 * confirmed the client is still looking at the same window
+		 * (as happens when switch-client -t targets a pane in the
+		 * already-current window, e.g. clicking a pane name in a
+		 * second #{P:} status line: the default MouseDown1Status
+		 * binding resolves that click to switch-client -t=, which
+		 * reaches here regardless of whether anything besides the
+		 * active pane changed). Redrawing unconditionally here
+		 * forced a full window redraw for what should have been
+		 * just an active-pane change, already handled narrowly by
+		 * window_set_active_pane() and window_redraw_active_switch()
+		 * before this is reached.
+		 *
+		 * old and s may be the same session object, whose curw was
+		 * already updated to the new window before this function was
+		 * called - old->curw and s->curw would then read the same,
+		 * already-current value, so comparing them can never detect
+		 * a same-session window change. Compare against the client's
+		 * own cached scene instead, which only reflects what it has
+		 * actually drawn.
+		 */
+		if (old == NULL || old != s ||
+		    !redraw_client_has_window(c, s->curw->window))
+			server_redraw_client(c);
 	}
 
 	server_check_unattached();
@@ -1391,19 +1417,15 @@ server_client_repeat_time(struct client *c, struct key_binding *bd)
 	return (repeat);
 }
 
-/* Handle a key press which closes a dead pane. */
+/* Handle a key press on a dead pane waiting for a key. */
 static int
 server_client_handle_dead_key(struct window_pane *wp, key_code key)
 {
-	int	remain_on_exit;
-
 	if (wp == NULL ||
 	    (~wp->flags & PANE_EXITED) ||
 	    KEYC_IS_MOUSE(key) ||
-	    KEYC_IS_PASTE(key))
+	    KEYC_IS_PASTE(key) ||
-		return (0);
+	    options_get_number(wp->options, "remain-on-exit") != 3)
-	remain_on_exit = options_get_number(wp->options, "remain-on-exit");
-	if (remain_on_exit != 3 && remain_on_exit != 4)
 		return (0);
 	options_set_number(wp->options, "remain-on-exit", 0);
 	server_destroy_pane(wp, 0);
@@ -1466,8 +1488,19 @@ server_client_key_callback(struct cmdq_item *item, void *data)
 		/*
 		 * Mouse drag is in progress, so fire the callback (now that
 		 * the mouse event is valid).
+		 *
+		 * Start a synchronized-output region here rather than
+		 * leaving it to whatever redraw eventually follows: a drag
+		 * callback may write directly via the pane's fast path
+		 * immediately, with any correction only arriving later via
+		 * redraw_client_damage(), which opens its own sync region.
+		 * Since tty_sync_end() is only called once, at the very end
+		 * of this client's pass in server_client_reset_state(),
+		 * starting it here merges both into one atomic terminal
+		 * update instead of two visible frames.
 		 */
 		if ((key & KEYC_MASK_KEY) == KEYC_DRAGGING) {
+			tty_sync_start(&c->tty);
 			c->tty.mouse_drag_update(c, m);
 			goto out;
 		}
@@ -1760,10 +1793,9 @@ server_client_handle_key0(struct client *c, struct key_event *event,
 	}
 
 	/*
-	 * Key presses in overlay mode, dead panes waiting for a key, modal cancel
+	 * Key presses in overlay mode, for panes capturing all keys and in the
-	 * keys, panes capturing all keys and the command prompt are special cases.
+	 * command prompt are a special case. The queue might be blocked so they
-	 * The queue might be blocked so they need to be processed immediately
+	 * need to be processed immediately rather than queued.
-	 * rather than queued.
 	 */
 	if (~c->flags & CLIENT_READONLY) {
 		if (c->message_string != NULL) {
@@ -1785,18 +1817,12 @@ server_client_handle_key0(struct client *c, struct key_event *event,
 		server_client_clear_overlay(c);
 
 		wp = s->curw->window->active;
-		if (server_client_handle_dead_key(wp, event->key))
-			return (0);
-		if (wp != NULL && wp == wp->window->modal &&
-		    (wp->flags & PANE_CLOSEONCANCEL) &&
-		    (event->key == '\033' || event->key == ('c'|KEYC_CTRL))) {
-			server_kill_pane(wp);
-			return (0);
-		}
 		if (wp != NULL &&
 		    (wp->flags & PANE_CAPTUREALLKEYS) &&
 		    TAILQ_EMPTY(&wp->modes) &&
 		    !KEYC_IS_MOUSE(event->key)) {
+			if (server_client_handle_dead_key(wp, event->key))
+				return (0);
 			if (~wp->flags & PANE_EXITED) {
 				window_pane_key(wp, c, s, s->curw, event->key,
 				    &event->m);
@@ -1911,7 +1937,12 @@ server_client_loop(void)
 
 	/*
 	 * Any windows will have been redrawn as part of clients, so clear
-	 * their flags now.
+	 * their flags now. A client whose redraw was deferred this pass
+	 * (waiting for outstanding tty output to drain) has already
+	 * escalated to CLIENT_REDRAWWINDOW or CLIENT_REDRAWSCROLLBARS in
+	 * server_client_check_redraw() to cover whatever it is about to
+	 * lose here, so PANE_REDRAW/PANE_REDRAWSCROLLBAR and window damage
+	 * can simply be cleared unconditionally.
 	 */
 	RB_FOREACH(w, windows, &windows) {
 		TAILQ_FOREACH(wp, &w->panes, entry) {
@@ -1922,6 +1953,8 @@ server_client_loop(void)
 			wp->flags &= ~(PANE_REDRAW|PANE_REDRAWSCROLLBAR|
 			    PANE_ACTIVITY);
 		}
+		redraw_free_damage(w);
+
 		check_window_name(w);
 	}
 
@@ -2470,6 +2503,8 @@ server_client_any_pane_redraw(struct client *c)
 
 	if (c->flags & CLIENT_REDRAWWINDOW)
 		return (1);
+	if (!TAILQ_EMPTY(&w->damage))
+		return (1);
 	TAILQ_FOREACH(wp, &w->panes, entry) {
 		if (wp->flags & (PANE_REDRAW|PANE_REDRAWSCROLLBAR))
 			return (1);
@@ -2515,7 +2550,12 @@ server_client_check_redraw(struct client *c)
 	/*
 	 * If there is outstanding data, defer the redraw until it has been
 	 * consumed. We can just add a timer to get out of the event loop and
-	 * end up back here.
+	 * end up back here. server_client_loop() clears PANE_REDRAW,
+	 * PANE_REDRAWSCROLLBAR and window damage unconditionally every pass,
+	 * so escalate to a coarser, persistent client flag that survives
+	 * that clear and forces a full catch-up redraw once this client is
+	 * unblocked, rather than trying to keep the fine-grained state
+	 * around for a retry.
 	 */
 	n = EVBUFFER_LENGTH(tty->out);
 	if (n != 0 || (tty->flags & TTY_BLOCK)) {
@@ -2529,6 +2569,8 @@ server_client_check_redraw(struct client *c)
 			log_debug("redraw timer started");
 			evtimer_add(&ev, &tv);
 		}
+		if (!TAILQ_EMPTY(&w->damage))
+			c->flags |= CLIENT_REDRAWWINDOW;
 		TAILQ_FOREACH(wp, &w->panes, entry) {
 			if (wp->flags & PANE_REDRAW) {
 				c->flags |= CLIENT_REDRAWWINDOW;
@@ -2562,6 +2604,19 @@ server_client_check_redraw(struct client *c)
 				redraw_pane_scrollbar(c, wp);
 			}
 		}
+
+		/*
+		 * Window damage is also what makes server_client_any_pane_
+		 * redraw() decide a redraw is needed at all, independently of
+		 * any CLIENT_ALLREDRAWFLAGS bit. Every current damage source
+		 * happens to set one of those flags too, so the block below
+		 * always consumes it - but consume it here too in case that
+		 * ever stops holding, since server_client_loop() clears
+		 * window damage unconditionally every pass regardless of
+		 * whether it was actually drawn.
+		 */
+		if (!TAILQ_EMPTY(&w->damage) && (~c->flags & CLIENT_ALLREDRAWFLAGS))
+			redraw_client_damage(c);
 	}
 
 	/*
@@ -2575,6 +2630,7 @@ server_client_check_redraw(struct client *c)
 		}
 		server_client_set_progress_bar(c);
 		redraw_screen(c);
+		redraw_client_damage(c);
 	}
 
 	/* Put the tty back how it was. */

server-fn.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: server-fn.c,v 1.153 2026/09/10 11:02:18 nicm Exp $ */
+/* $OpenBSD: server-fn.c,v 1.152 2026/09/03 19:12:36 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -386,7 +386,6 @@ server_destroy_pane(struct window_pane *wp, int notify)
 	case 0:
 		break;
 	case 2:
-	case 4:
 		if (WIFEXITED(wp->status) && WEXITSTATUS(wp->status) == 0)
 			break;
 		/* FALLTHROUGH */

tmux.1

@@ -1,4 +1,4 @@
-.\" $OpenBSD: tmux.1,v 1.1170 2026/09/11 10:17:16 nicm Exp $
+.\" $OpenBSD: tmux.1,v 1.1168 2026/09/09 07:03:39 nicm Exp $
 .\"
 .\" Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
 .\"
@@ -14,7 +14,7 @@
 .\" IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 .\" OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: September 11 2026 $
+.Dd $Mdocdate: September 9 2026 $
 .Dt TMUX 1
 .Os
 .Sh NAME
@@ -3655,7 +3655,7 @@ but a different format may be specified with
 .Fl F .
 .Tg newp
 .It Xo Ic new\-pane
-.Op Fl AbCDefhIkKLMOPvWZ
+.Op Fl AbCdefhIkKLMOPvWZ
 .Op Fl B Ar border\-lines
 .Op Fl c Ar start\-directory
 .Op Fl e Ar environment
@@ -3717,13 +3717,6 @@ all keys, including the prefix key, are passed directly to the modal pane.
 With
 .Fl C ,
 the modal pane is closed when the mouse is clicked outside it.
-With
-.Fl D ,
-the modal pane is closed when
-.Ql Escape
-or
-.Ql C-c
-is pressed.
 .Pp
 The
 .Fl L
@@ -5980,8 +5973,6 @@ single lines using ACS or UTF\-8 characters
 double lines using UTF\-8 characters
 .It heavy
 heavy lines using UTF\-8 characters
-.It rounded
-single lines with rounded corners using UTF\-8 characters
 .It simple
 simple ASCII characters
 .It number
@@ -6337,7 +6328,7 @@ uses when the colour with that index is requested.
 The index may be from zero to 255.
 .Pp
 .It Xo Ic remain\-on\-exit
-.Op Ic on | off | failed | key | failed\-key
+.Op Ic on | off | failed | key
 .Xc
 A pane with this flag set is not destroyed when the program running in it
 exits.
@@ -6347,10 +6338,6 @@ then only when the program exit status is not zero.
 If set to
 .Ic key ,
 the pane stays open and closes when a key is pressed.
-If set to
-.Ic failed\-key ,
-the pane stays open and closes when a key is pressed only if the program exit
-status is not zero.
 The pane may be reactivated with the
 .Ic respawn\-pane
 command.

tmux.h

@@ -1,4 +1,4 @@
-/* $OpenBSD: tmux.h,v 1.1440 2026/09/11 10:17:16 nicm Exp $ */
+/* $OpenBSD: tmux.h,v 1.1438 2026/09/09 08:30:05 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -69,6 +69,7 @@ struct options_array_item;
 struct options_entry;
 struct prompt;
 struct window_pane_prompt;
+struct redraw_damage;
 struct redraw_scene;
 struct redraw_span;
 struct screen_write_citem;
@@ -1150,8 +1151,7 @@ enum pane_lines {
 	PANE_LINES_SIMPLE,
 	PANE_LINES_NUMBER,
 	PANE_LINES_SPACES,
-	PANE_LINES_NONE,
+	PANE_LINES_NONE
-	PANE_LINES_ROUNDED
 };
 
 /* Pane border indicator option. */
@@ -1340,7 +1340,6 @@ struct window_pane {
 #define PANE_CLOSEONCLICK 0x80000
 #define PANE_CAPTUREALLKEYS 0x100000
 #define PANE_FLOATOVERZOOM 0x200000
-#define PANE_CLOSEONCANCEL 0x400000
 
 	bitstr_t	*sync_dirty;
 	u_int		 sync_dirty_size;
@@ -1429,6 +1428,7 @@ struct window_pane {
 TAILQ_HEAD(window_panes, window_pane);
 TAILQ_HEAD(window_panes_zindex, window_pane);
 RB_HEAD(window_pane_tree, window_pane);
+TAILQ_HEAD(redraw_damages, redraw_damage);
 
 /* Window structure. */
 struct window {
@@ -1472,6 +1472,9 @@ struct window {
 
 	uint64_t		 redraw_scene_generation;
 
+	struct redraw_damages	 damage;
+	u_int			 damage_count;
+
 	struct menu_data	*menu;
 	u_int			 menu_last_px;
 	u_int			 menu_last_py;
@@ -1844,7 +1847,7 @@ struct tty {
 };
 
 /* Terminal command context. */
-typedef void (*tty_ctx_redraw_cb)(const struct tty_ctx *);
+typedef void (*tty_ctx_redraw_cb)(const struct tty_ctx *, u_int, u_int);
 typedef int (*tty_ctx_set_client_cb)(struct tty_ctx *, struct client *);
 struct tty_ctx {
 	struct screen		*s;
@@ -3659,8 +3662,12 @@ void	 redraw_screen(struct client *);
 void	 redraw_pane(struct client *, struct window_pane *);
 void	 redraw_pane_scrollbar(struct client *, struct window_pane *);
 void	 redraw_free_scene(struct redraw_scene *);
+int	 redraw_client_has_window(struct client *, struct window *);
 void	 redraw_invalidate_scene(struct window *);
 void	 redraw_invalidate_all_scenes(void);
+void	 redraw_damage_window(struct window *, u_int, u_int, u_int, u_int);
+void	 redraw_free_damage(struct window *);
+void	 redraw_client_damage(struct client *);
 int	 redraw_get_status_border_cell_type(struct redraw_span **, u_int);
 
 /* screen.c */
@@ -3834,6 +3841,8 @@ int		 window_pane_get_pane_status(struct window_pane *);
 struct style_range *window_pane_status_get_range(struct window_pane *, u_int,
 		     u_int);
 int		 window_pane_is_floating(struct window_pane *);
+void		 window_pane_redraw_floating(struct window *,
+		     struct window_pane *, int, int, int, int);
 
 /* window-border.c */
 void		 window_set_fill_cells(struct window *);

tty.c

@@ -1120,7 +1120,7 @@ tty_redraw_region(struct tty *tty, const struct tty_ctx *ctx)
 	 */
 	if (tty_large_region(tty, ctx) || ctx->flags & TTY_CTX_PANE_OBSCURED) {
 		log_debug("%s: %s large region redraw", __func__, c->name);
-		ctx->redraw_cb(ctx);
+		ctx->redraw_cb(ctx, ctx->orupper, ctx->orlower - ctx->orupper + 1);
 		return;
 	}
 
@@ -2032,7 +2032,7 @@ tty_cmd_alignmenttest(struct tty *tty, const struct tty_ctx *ctx)
 
 	if ((ctx->flags & TTY_CTX_WINDOW_BIGGER) ||
 	    c->overlay_check != NULL) {
-		ctx->redraw_cb(ctx);
+		ctx->redraw_cb(ctx, 0, ctx->sy);
 		return;
 	}
 
@@ -2114,7 +2114,7 @@ tty_cmd_cells(struct tty *tty, const struct tty_ctx *ctx)
 		    tty->cy == tty->rlower)
 			tty_draw_pane(tty, ctx, ctx->ocy);
 		else
-			ctx->redraw_cb(ctx);
+			ctx->redraw_cb(ctx, ctx->ocy, 1);
 		return;
 	}
 

window-border.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: window-border.c,v 1.4 2026/09/11 10:17:16 nicm Exp $ */
+/* $OpenBSD: window-border.c,v 1.3 2026/07/23 09:38:27 nicm Exp $ */
 
 /*
  * Copyright (c) 2026 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -120,10 +120,6 @@ window_get_border_cell(struct window_pane *wp, enum pane_lines pane_lines,
 		gc->attr &= ~GRID_ATTR_CHARSET;
 		utf8_copy(&gc->data, tty_acs_heavy_borders(cell_type));
 		break;
-	case PANE_LINES_ROUNDED:
-		gc->attr &= ~GRID_ATTR_CHARSET;
-		utf8_copy(&gc->data, tty_acs_rounded_borders(cell_type));
-		break;
 	case PANE_LINES_SIMPLE:
 		gc->attr &= ~GRID_ATTR_CHARSET;
 		utf8_set(&gc->data, SIMPLE_BORDERS[cell_type]);

window.c

@@ -415,6 +415,7 @@ window_create(u_int sx, u_int sy, u_int xpixel, u_int ypixel)
 	TAILQ_INIT(&w->panes);
 	TAILQ_INIT(&w->z_index);
 	TAILQ_INIT(&w->last_panes);
+	TAILQ_INIT(&w->damage);
 	w->active = NULL;
 
 	w->lastlayout = -1;
@@ -460,6 +461,7 @@ window_destroy(struct window *w)
 
 	menu_destroy(w);
 	window_destroy_panes(w);
+	redraw_free_damage(w);
 
 	if (event_initialized(&w->name_event))
 		evtimer_del(&w->name_event);
@@ -711,6 +713,7 @@ int
 window_set_active_pane(struct window *w, struct window_pane *wp, int notify)
 {
 	struct window_pane *lastwp;
+	int		    unzoomed;
 
 	log_debug("%s: pane %%%u", __func__, wp->id);
 
@@ -718,7 +721,8 @@ window_set_active_pane(struct window *w, struct window_pane *wp, int notify)
 		return (0);
 	if (w->modal != NULL && wp != w->modal)
 		return (0);
-	if ((w->flags & WINDOW_ZOOMED) && !window_pane_is_visible(wp))
+	unzoomed = (w->flags & WINDOW_ZOOMED) && !window_pane_is_visible(wp);
+	if (unzoomed)
 		window_unzoom(w, 1);
 	lastwp = w->active;
 
@@ -735,7 +739,19 @@ window_set_active_pane(struct window *w, struct window_pane *wp, int notify)
 	}
 
 	tty_update_window_offset(w);
-	server_redraw_window(w);
+
+	/*
+	 * Unzooming changes every pane's geometry and needs a full window
+	 * redraw. Otherwise, only the previous and new active pane's border
+	 * and status appearance changed, so avoid redrawing unaffected pane
+	 * content.
+	 */
+	if (unzoomed)
+		server_redraw_window(w);
+	else {
+		server_redraw_window_borders(w);
+		server_status_window(w);
+	}
 
 	if (notify)
 		window_fire_pane_changed(w, w->active, lastwp);
@@ -2906,3 +2922,109 @@ window_pane_is_floating(struct window_pane *wp)
 		return (0);
 	return (1);
 }
+
+/*
+ * Report damage for a floating pane's rectangle, grown by one cell on every
+ * side - a floating pane draws its border frame at xoff-1/yoff-1 through
+ * xoff+sx/yoff+sy (see the "floating" case in screen-redraw.c), one cell
+ * outside its own content area, so damage for just the content area leaves
+ * the frame's previous position undrawn as the pane moves. If a scrollbar
+ * is reserved, its side of the frame is pushed out further still by its
+ * width and padding (also matched in screen-redraw.c), so grow that side
+ * to match.
+ */
+static void
+window_pane_damage_floating(struct window *w, struct window_pane *wp,
+    int xoff, int yoff, int sx, int sy)
+{
+	int	x0, x1, y0, y1, sb_left = 0, sb_right = 0;
+
+	if (window_pane_scrollbar_reserve(wp)) {
+		if (w->sb_pos == PANE_SCROLLBARS_LEFT)
+			sb_left = wp->scrollbar_style.width +
+			    wp->scrollbar_style.pad;
+		else
+			sb_right = wp->scrollbar_style.width +
+			    wp->scrollbar_style.pad;
+	}
+
+	x0 = xoff - 1 - sb_left;
+	x1 = xoff + sx + sb_right;
+	y0 = yoff - 1;
+	y1 = yoff + sy;
+	if (x0 < 0)
+		x0 = 0;
+	if (y0 < 0)
+		y0 = 0;
+	if (x1 < x0 || y1 < y0)
+		return;
+	redraw_damage_window(w, (u_int)x0, (u_int)y0, (u_int)(x1 - x0) + 1,
+	    (u_int)(y1 - y0) + 1);
+}
+
+/*
+ * Whether a pane's scrollbar strip - not its whole body - intersects a
+ * window-coordinate rectangle. A reserved scrollbar occupies a strip of
+ * scrollbar_style.width+pad columns just outside the pane's own content
+ * area (see the scrollbar-reserve case in layout_fix_panes(), layout.c),
+ * on whichever side w->sb_pos points to.
+ */
+static int
+window_pane_scrollbar_intersects(struct window *w, struct window_pane *wp,
+    u_int x, u_int y, u_int sx, u_int sy)
+{
+	int	sb_x, sb_w, ix = (int)x, iy = (int)y, isx = (int)sx;
+	int	isy = (int)sy;
+
+	if (!window_pane_scrollbar_reserve(wp))
+		return (0);
+	sb_w = wp->scrollbar_style.width + wp->scrollbar_style.pad;
+	if (w->sb_pos == PANE_SCROLLBARS_LEFT)
+		sb_x = (int)wp->xoff - sb_w;
+	else
+		sb_x = (int)wp->xoff + (int)wp->sx;
+
+	return (sb_x < ix + isx && sb_x + sb_w > ix &&
+	    (int)wp->yoff < iy + isy && (int)wp->yoff + (int)wp->sy > iy);
+}
+
+/*
+ * Report damage for only a floating pane's old and new area, rather than
+ * the whole window - a floating pane move or resize only disturbs what it
+ * was covering and what it now covers. Scrollbars aren't covered by the
+ * damage system, so a pane whose *scrollbar strip* (not its whole body)
+ * intersects either area is still flagged directly for a scrollbar redraw.
+ * Checking the whole pane body here, rather than just its narrow scrollbar
+ * strip, meant merely dragging over a pane's ordinary content set
+ * PANE_REDRAWSCROLLBAR on every such pane on every motion event, triggering
+ * a needless scrollbar redraw (and the redraw pass it forces) each time
+ * even though the scrollbar itself never moved.
+ *
+ * Shared by every command that drags a floating pane around by the mouse:
+ * resize-pane's own border drag (cmd-resize-pane.c), move-pane -M's
+ * alternate Alt-drag (cmd-join-pane.c), and split-window/new-pane's
+ * interactive resize of a newly-created floating pane (cmd-split-window.c).
+ */
+void
+window_pane_redraw_floating(struct window *w, struct window_pane *wp,
+    int old_xoff, int old_yoff, int old_sx, int old_sy)
+{
+	struct window_pane	*loop;
+
+	window_pane_damage_floating(w, wp, old_xoff, old_yoff, old_sx,
+	    old_sy);
+	window_pane_damage_floating(w, wp, wp->xoff, wp->yoff, wp->sx,
+	    wp->sy);
+
+	TAILQ_FOREACH(loop, &w->panes, entry) {
+		if (window_pane_scrollbar_intersects(w, loop,
+		    (u_int)old_xoff, (u_int)old_yoff, (u_int)old_sx,
+		    (u_int)old_sy) ||
+		    window_pane_scrollbar_intersects(w, loop, wp->xoff,
+		    wp->yoff, wp->sx, wp->sy))
+			loop->flags |= PANE_REDRAWSCROLLBAR;
+	}
+
+	/* Session status formats may depend on the pane's new geometry. */
+	server_status_window(w);
+}