From a8520ba59e32133414c710b26ec23bf3c19f8b23 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Sun, 17 May 2026 16:01:42 +0000
Subject: [PATCH] Bring over some of layout and positioning code for floating
 panes, by Michael Grant.

---
 cmd-break-pane.c  |   2 +-
 cmd-join-pane.c   |   2 +-
 cmd-select-pane.c |   2 +-
 format.c          |  10 +--
 layout-custom.c   | 176 +++++++++++++++++++++++++++++++++-------------
 layout-set.c      |  12 ++--
 layout.c          |  95 +++++++++++++++++++------
 log.c             |   2 +
 server-fn.c       |   2 +-
 tmux.h            |  22 +++---
 window-tree.c     |   4 +-
 window.c          |  86 +++++++++++-----------
 12 files changed, 282 insertions(+), 133 deletions(-)

diff --git a/cmd-break-pane.c b/cmd-break-pane.c
index add3743b..790b8df2 100644
--- a/cmd-break-pane.c
+++ b/cmd-break-pane.c
@@ -73,7 +73,7 @@ cmd_break_pane_exec(struct cmd *self, struct cmdq_item *item)
 	}
 	server_unzoom_window(w);
 
-	if (window_count_panes(w) == 1) {
+	if (window_count_panes(w, 1) == 1) {
 		if (server_link_window(src_s, wl, dst_s, idx, 0,
 		    !args_has(args, 'd'), &cause) != 0) {
 			cmdq_error(item, "%s", cause);
diff --git a/cmd-join-pane.c b/cmd-join-pane.c
index 6eb0ea65..f8975a67 100644
--- a/cmd-join-pane.c
+++ b/cmd-join-pane.c
@@ -171,7 +171,7 @@ cmd_join_pane_exec(struct cmd *self, struct cmdq_item *item)
 	} else
 		server_status_session(dst_s);
 
-	if (window_count_panes(src_w) == 0)
+	if (window_count_panes(src_w, 1) == 0)
 		server_kill_window(src_w, 1);
 	else
 		notify_window("window-layout-changed", src_w);
diff --git a/cmd-select-pane.c b/cmd-select-pane.c
index 3cabe07e..51c29ec2 100644
--- a/cmd-select-pane.c
+++ b/cmd-select-pane.c
@@ -103,7 +103,7 @@ cmd_select_pane_exec(struct cmd *self, struct cmdq_item *item)
 		 * spawned without being visited (for example split-window -d).
 		 */
 		lastwp = TAILQ_FIRST(&w->last_panes);
-		if (lastwp == NULL && window_count_panes(w) == 2) {
+		if (lastwp == NULL && window_count_panes(w, 1) == 2) {
 			lastwp = TAILQ_PREV(w->active, window_panes, entry);
 			if (lastwp == NULL)
 				lastwp = TAILQ_NEXT(w->active, entry);
diff --git a/format.c b/format.c
index 8a0accf7..472316ec 100644
--- a/format.c
+++ b/format.c
@@ -2046,7 +2046,7 @@ static void *
 format_cb_pane_bottom(struct format_tree *ft)
 {
 	if (ft->wp != NULL)
-		return (format_printf("%u", ft->wp->yoff + ft->wp->sy - 1));
+		return (format_printf("%d", ft->wp->yoff + ft->wp->sy - 1));
 	return (NULL);
 }
 
@@ -2205,7 +2205,7 @@ static void *
 format_cb_pane_left(struct format_tree *ft)
 {
 	if (ft->wp != NULL)
-		return (format_printf("%u", ft->wp->xoff));
+		return (format_printf("%d", ft->wp->xoff));
 	return (NULL);
 }
 
@@ -2329,7 +2329,7 @@ static void *
 format_cb_pane_right(struct format_tree *ft)
 {
 	if (ft->wp != NULL)
-		return (format_printf("%u", ft->wp->xoff + ft->wp->sx - 1));
+		return (format_printf("%d", ft->wp->xoff + ft->wp->sx - 1));
 	return (NULL);
 }
 
@@ -2371,7 +2371,7 @@ static void *
 format_cb_pane_top(struct format_tree *ft)
 {
 	if (ft->wp != NULL)
-		return (format_printf("%u", ft->wp->yoff));
+		return (format_printf("%d", ft->wp->yoff));
 	return (NULL);
 }
 
@@ -2918,7 +2918,7 @@ static void *
 format_cb_window_panes(struct format_tree *ft)
 {
 	if (ft->w != NULL)
-		return (format_printf("%u", window_count_panes(ft->w)));
+		return (format_printf("%u", window_count_panes(ft->w, 1)));
 	return (NULL);
 }
 
diff --git a/layout-custom.c b/layout-custom.c
index 27d5bf82..aa36d2c4 100644
--- a/layout-custom.c
+++ b/layout-custom.c
@@ -27,10 +27,11 @@ static struct layout_cell	*layout_find_bottomright(struct layout_cell *);
 static u_short			 layout_checksum(const char *);
 static int			 layout_append(struct layout_cell *, char *,
 				     size_t);
-static struct layout_cell	*layout_construct(struct layout_cell *,
-				     const char **);
+static int			 layout_construct(struct layout_cell *,
+				     const char **, struct layout_cell **,
+				     struct layout_cell **);
 static void			 layout_assign(struct window_pane **,
-				     struct layout_cell *);
+				     struct layout_cell *, int);
 
 /* Find the bottom-right cell. */
 static struct layout_cell *
@@ -58,14 +59,30 @@ layout_checksum(const char *layout)
 
 /* Dump layout as a string. */
 char *
-layout_dump(__unused struct window *w, struct layout_cell *root)
+layout_dump(struct window *w, struct layout_cell *root)
 {
-	char	layout[8192], *out;
+	char			 layout[8192], *out;
+	int			 bracket = 0;
+	struct window_pane	*wp;
 
 	*layout = '\0';
 	if (layout_append(root, layout, sizeof layout) != 0)
 		return (NULL);
 
+	TAILQ_FOREACH(wp, &w->z_index, zentry) {
+		if (~wp->flags & PANE_FLOATING)
+			break;
+		if (!bracket) {
+			strlcat(layout, "<", sizeof layout);
+			bracket = 1;
+		}
+		if (layout_append(wp->layout_cell, layout, sizeof layout) != 0)
+			return (NULL);
+		strlcat(layout, ",", sizeof layout);
+	}
+	if (bracket)
+		layout[strlen(layout) - 1] = '>';
+
 	xasprintf(&out, "%04hx,%s", layout_checksum(layout), layout);
 	return (out);
 }
@@ -81,12 +98,13 @@ layout_append(struct layout_cell *lc, char *buf, size_t len)
 
 	if (len == 0)
 		return (-1);
-
+	if (lc == NULL)
+		return (0);
 	if (lc->wp != NULL) {
-		tmplen = xsnprintf(tmp, sizeof tmp, "%ux%u,%u,%u,%u",
+		tmplen = xsnprintf(tmp, sizeof tmp, "%ux%u,%d,%d,%u",
 		    lc->sx, lc->sy, lc->xoff, lc->yoff, lc->wp->id);
 	} else {
-		tmplen = xsnprintf(tmp, sizeof tmp, "%ux%u,%u,%u",
+		tmplen = xsnprintf(tmp, sizeof tmp, "%ux%u,%d,%d",
 		    lc->sx, lc->sy, lc->xoff, lc->yoff);
 	}
 	if (tmplen > (sizeof tmp) - 1)
@@ -109,6 +127,7 @@ layout_append(struct layout_cell *lc, char *buf, size_t len)
 		}
 		buf[strlen(buf) - 1] = brackets[0];
 		break;
+	case LAYOUT_FLOATING:
 	case LAYOUT_WINDOWPANE:
 		break;
 	}
@@ -124,6 +143,7 @@ layout_check(struct layout_cell *lc)
 	u_int			 n = 0;
 
 	switch (lc->type) {
+	case LAYOUT_FLOATING:
 	case LAYOUT_WINDOWPANE:
 		break;
 	case LAYOUT_LEFTRIGHT:
@@ -156,7 +176,7 @@ layout_check(struct layout_cell *lc)
 int
 layout_parse(struct window *w, const char *layout, char **cause)
 {
-	struct layout_cell	*lc, *lcchild;
+	struct layout_cell	*lcchild, *tiled_lc = NULL, *floating_lc = NULL;
 	struct window_pane	*wp;
 	u_int			 npanes, ncells, sx = 0, sy = 0;
 	u_short			 csum;
@@ -174,20 +194,27 @@ layout_parse(struct window *w, const char *layout, char **cause)
 	}
 
 	/* Build the layout. */
-	lc = layout_construct(NULL, &layout);
-	if (lc == NULL) {
+	if (layout_construct(NULL, &layout, &tiled_lc, &floating_lc) != 0) {
 		*cause = xstrdup("invalid layout");
 		return (-1);
 	}
+	if (tiled_lc == NULL) {
+		/* A stub layout cell for an empty window. */
+		tiled_lc = layout_create_cell(NULL);
+		tiled_lc->type = LAYOUT_LEFTRIGHT;
+		layout_set_size(tiled_lc, w->sx, w->sy, 0, 0);
+	}
 	if (*layout != '\0') {
 		*cause = xstrdup("invalid layout");
 		goto fail;
 	}
 
 	/* Check this window will fit into the layout. */
+	npanes = window_count_panes(w, 1);
 	for (;;) {
-		npanes = window_count_panes(w);
-		ncells = layout_count_cells(lc);
+		ncells = layout_count_cells(tiled_lc);
+		if (floating_lc != NULL)
+			ncells += layout_count_cells(floating_lc);
 		if (npanes > ncells) {
 			xasprintf(cause, "have %u panes but need %u", npanes,
 			    ncells);
@@ -196,9 +223,17 @@ layout_parse(struct window *w, const char *layout, char **cause)
 		if (npanes == ncells)
 			break;
 
-		/* Fewer panes than cells - close the bottom right. */
-		lcchild = layout_find_bottomright(lc);
-		layout_destroy_cell(w, lcchild, &lc);
+		/*
+		 * Fewer panes than cells - close floating panes first
+		 * then close the bottom right until none remain.
+		 */
+		if (floating_lc != NULL && !TAILQ_EMPTY(&floating_lc->cells)) {
+			lcchild = TAILQ_FIRST(&floating_lc->cells);
+			layout_destroy_cell(w, lcchild, &floating_lc);
+		} else {
+			lcchild = layout_find_bottomright(tiled_lc);
+			layout_destroy_cell(w, lcchild, &tiled_lc);
+		}
 	}
 
 	/*
@@ -206,91 +241,108 @@ layout_parse(struct window *w, const char *layout, char **cause)
 	 * an incorrect top cell size - if it is larger than the top child then
 	 * correct that (if this is still wrong the check code will catch it).
 	 */
-	switch (lc->type) {
+
+	switch (tiled_lc->type) {
 	case LAYOUT_WINDOWPANE:
 		break;
 	case LAYOUT_LEFTRIGHT:
-		TAILQ_FOREACH(lcchild, &lc->cells, entry) {
+		TAILQ_FOREACH(lcchild, &tiled_lc->cells, entry) {
 			sy = lcchild->sy + 1;
 			sx += lcchild->sx + 1;
 		}
 		break;
 	case LAYOUT_TOPBOTTOM:
-		TAILQ_FOREACH(lcchild, &lc->cells, entry) {
+		TAILQ_FOREACH(lcchild, &tiled_lc->cells, entry) {
 			sx = lcchild->sx + 1;
 			sy += lcchild->sy + 1;
 		}
 		break;
+	case LAYOUT_FLOATING:
+		*cause = xstrdup("invalid layout");
+		goto fail;
 	}
-	if (lc->type != LAYOUT_WINDOWPANE && (lc->sx != sx || lc->sy != sy)) {
-		log_debug("fix layout %u,%u to %u,%u", lc->sx, lc->sy, sx,sy);
-		layout_print_cell(lc, __func__, 0);
-		lc->sx = sx - 1; lc->sy = sy - 1;
+	if (tiled_lc->type != LAYOUT_WINDOWPANE &&
+	    (tiled_lc->sx != sx || tiled_lc->sy != sy)) {
+		layout_print_cell(tiled_lc, __func__, 0);
+		tiled_lc->sx = sx - 1; tiled_lc->sy = sy - 1;
 	}
 
 	/* Check the new layout. */
-	if (!layout_check(lc)) {
+	if (!layout_check(tiled_lc)) {
 		*cause = xstrdup("size mismatch after applying layout");
 		goto fail;
 	}
 
-	/* Resize to the layout size. */
-	window_resize(w, lc->sx, lc->sy, -1, -1);
+	/* Resize window to the layout size. */
+	if (sx != 0 && sy != 0)
+		window_resize(w, tiled_lc->sx, tiled_lc->sy, -1, -1);
 
 	/* Destroy the old layout and swap to the new. */
 	layout_free_cell(w->layout_root);
-	w->layout_root = lc;
+	w->layout_root = tiled_lc;
 
 	/* Assign the panes into the cells. */
 	wp = TAILQ_FIRST(&w->panes);
-	layout_assign(&wp, lc);
+	if (tiled_lc != NULL)
+		layout_assign(&wp, tiled_lc, 0);
+	if (floating_lc != NULL)
+		layout_assign(&wp, floating_lc, PANE_FLOATING);
 
 	/* Update pane offsets and sizes. */
 	layout_fix_offsets(w);
 	layout_fix_panes(w, NULL);
 	recalculate_sizes();
+	layout_print_cell(tiled_lc, __func__, 0);
 
-	layout_print_cell(lc, __func__, 0);
+	/* Free the floating layout cell, no longer needed. */
+	if (floating_lc != NULL)
+		layout_free_cell(floating_lc);
 
 	notify_window("window-layout-changed", w);
 
 	return (0);
 
 fail:
-	layout_free_cell(lc);
+	layout_free_cell(tiled_lc);
+	layout_free_cell(floating_lc);
 	return (-1);
 }
 
 /* Assign panes into cells. */
 static void
-layout_assign(struct window_pane **wp, struct layout_cell *lc)
+layout_assign(struct window_pane **wp, struct layout_cell *lc, int flags)
 {
 	struct layout_cell	*lcchild;
 
+	if (lc == NULL)
+		return;
+
 	switch (lc->type) {
 	case LAYOUT_WINDOWPANE:
 		layout_make_leaf(lc, *wp);
+		(*wp)->flags |= flags;
 		*wp = TAILQ_NEXT(*wp, entry);
 		return;
 	case LAYOUT_LEFTRIGHT:
 	case LAYOUT_TOPBOTTOM:
+	case LAYOUT_FLOATING:
 		TAILQ_FOREACH(lcchild, &lc->cells, entry)
-			layout_assign(wp, lcchild);
+			layout_assign(wp, lcchild, 1);
 		return;
 	}
 }
 
-/* Construct a cell from all or part of a layout tree. */
 static struct layout_cell *
-layout_construct(struct layout_cell *lcparent, const char **layout)
+layout_construct_cell(struct layout_cell *lcparent, const char **layout)
 {
-	struct layout_cell     *lc, *lcchild;
-	u_int			sx, sy, xoff, yoff;
+	struct layout_cell     *lc;
+	u_int			sx, sy;
+	int			xoff, yoff;
 	const char	       *saved;
 
 	if (!isdigit((u_char) **layout))
 		return (NULL);
-	if (sscanf(*layout, "%ux%u,%u,%u", &sx, &sy, &xoff, &yoff) != 4)
+	if (sscanf(*layout, "%ux%u,%d,%d", &sx, &sy, &xoff, &yoff) != 4)
 		return (NULL);
 
 	while (isdigit((u_char) **layout))
@@ -325,17 +377,41 @@ layout_construct(struct layout_cell *lcparent, const char **layout)
 	lc->xoff = xoff;
 	lc->yoff = yoff;
 
+	return (lc);
+}
+
+/*
+ * Given a character string layout, recursively construct cells.
+ * Possible return values:
+ *  lc LAYOUT_WINDOWPANE, no children
+ *  lc LAYOUT_LEFTRIGHT or LAYOUT_TOPBOTTOM, with children
+ *  floating_lc LAYOUT_FLOATING, with children
+ */
+static int
+layout_construct(struct layout_cell *lcparent, const char **layout,
+    struct layout_cell **lc, struct layout_cell **floating_lc)
+{
+	struct layout_cell	*lcchild, *saved_lc;
+
+	*lc = layout_construct_cell(lcparent, layout);
+
 	switch (**layout) {
 	case ',':
 	case '}':
 	case ']':
+	case '>':
 	case '\0':
-		return (lc);
+		return (0);
 	case '{':
-		lc->type = LAYOUT_LEFTRIGHT;
+		(*lc)->type = LAYOUT_LEFTRIGHT;
 		break;
 	case '[':
-		lc->type = LAYOUT_TOPBOTTOM;
+		(*lc)->type = LAYOUT_TOPBOTTOM;
+		break;
+	case '<':
+		saved_lc = *lc;
+		*lc = layout_create_cell(lcparent);
+		(*lc)->type = LAYOUT_FLOATING;
 		break;
 	default:
 		goto fail;
@@ -343,13 +419,12 @@ layout_construct(struct layout_cell *lcparent, const char **layout)
 
 	do {
 		(*layout)++;
-		lcchild = layout_construct(lc, layout);
-		if (lcchild == NULL)
+		if (layout_construct(*lc, layout, &lcchild, floating_lc) != 0)
 			goto fail;
-		TAILQ_INSERT_TAIL(&lc->cells, lcchild, entry);
+		TAILQ_INSERT_TAIL(&(*lc)->cells, lcchild, entry);
 	} while (**layout == ',');
 
-	switch (lc->type) {
+	switch ((*lc)->type) {
 	case LAYOUT_LEFTRIGHT:
 		if (**layout != '}')
 			goto fail;
@@ -358,14 +433,21 @@ layout_construct(struct layout_cell *lcparent, const char **layout)
 		if (**layout != ']')
 			goto fail;
 		break;
+	case LAYOUT_FLOATING:
+		if (**layout != '>')
+			goto fail;
+		*floating_lc = *lc;
+		*lc = saved_lc;
+		break;
 	default:
 		goto fail;
 	}
 	(*layout)++;
 
-	return (lc);
+	return (0);
 
 fail:
-	layout_free_cell(lc);
-	return (NULL);
+	layout_free_cell(*lc);
+	layout_free_cell(*floating_lc);
+	return (-1);
 }
diff --git a/layout-set.c b/layout-set.c
index bd68f663..f9944ed9 100644
--- a/layout-set.c
+++ b/layout-set.c
@@ -133,7 +133,7 @@ layout_set_even(struct window *w, enum layout_type type)
 	layout_print_cell(w->layout_root, __func__, 1);
 
 	/* Get number of panes. */
-	n = window_count_panes(w);
+	n = window_count_panes(w, 0);
 	if (n <= 1)
 		return;
 
@@ -201,7 +201,7 @@ layout_set_main_h(struct window *w)
 	layout_print_cell(w->layout_root, __func__, 1);
 
 	/* Get number of panes. */
-	n = window_count_panes(w);
+	n = window_count_panes(w, 0);
 	if (n <= 1)
 		return;
 	n--;	/* take off main pane */
@@ -299,7 +299,7 @@ layout_set_main_h_mirrored(struct window *w)
 	layout_print_cell(w->layout_root, __func__, 1);
 
 	/* Get number of panes. */
-	n = window_count_panes(w);
+	n = window_count_panes(w, 0);
 	if (n <= 1)
 		return;
 	n--;	/* take off main pane */
@@ -397,7 +397,7 @@ layout_set_main_v(struct window *w)
 	layout_print_cell(w->layout_root, __func__, 1);
 
 	/* Get number of panes. */
-	n = window_count_panes(w);
+	n = window_count_panes(w, 0);
 	if (n <= 1)
 		return;
 	n--;	/* take off main pane */
@@ -495,7 +495,7 @@ layout_set_main_v_mirrored(struct window *w)
 	layout_print_cell(w->layout_root, __func__, 1);
 
 	/* Get number of panes. */
-	n = window_count_panes(w);
+	n = window_count_panes(w, 0);
 	if (n <= 1)
 		return;
 	n--;	/* take off main pane */
@@ -593,7 +593,7 @@ layout_set_tiled(struct window *w)
 	layout_print_cell(w->layout_root, __func__, 1);
 
 	/* Get number of panes. */
-	n = window_count_panes(w);
+	n = window_count_panes(w, 0);
 	if (n <= 1)
 		return;
 
diff --git a/layout.c b/layout.c
index d3df5e7f..5afd697b 100644
--- a/layout.c
+++ b/layout.c
@@ -46,7 +46,10 @@ static int	layout_set_size_check(struct window *, struct layout_cell *,
 		    enum layout_type, int);
 static void	layout_resize_child_cells(struct window *,
 		    struct layout_cell *);
+void		layout_redistribute_cells(struct window *, struct layout_cell *,
+		    enum layout_type);
 
+/* Create a new layout cell. */
 struct layout_cell *
 layout_create_cell(struct layout_cell *lcparent)
 {
@@ -61,14 +64,15 @@ layout_create_cell(struct layout_cell *lcparent)
 	lc->sx = UINT_MAX;
 	lc->sy = UINT_MAX;
 
-	lc->xoff = UINT_MAX;
-	lc->yoff = UINT_MAX;
+	lc->xoff = INT_MAX;
+	lc->yoff = INT_MAX;
 
 	lc->wp = NULL;
 
 	return (lc);
 }
 
+/* Free a layout cell. */
 void
 layout_free_cell(struct layout_cell *lc)
 {
@@ -83,21 +87,40 @@ layout_free_cell(struct layout_cell *lc)
 			layout_free_cell(lcchild);
 		}
 		break;
+	case LAYOUT_FLOATING:
+		/*
+		 * A floating layout cell is only used temporarily while
+		 * select-layout constructs a layout. Remove the children from
+		 * the temporary layout, then free temporary floating layout
+		 * cell. Each floating pane has stub layout.
+		 */
+		while (!TAILQ_EMPTY(&lc->cells)) {
+			lcchild = TAILQ_FIRST(&lc->cells);
+			TAILQ_REMOVE(&lc->cells, lcchild, entry);
+			lcchild->parent = NULL;
+		}
+		break;
 	case LAYOUT_WINDOWPANE:
-		if (lc->wp != NULL)
+		if (lc->wp != NULL) {
+			lc->wp->layout_cell->parent = NULL;
 			lc->wp->layout_cell = NULL;
+		}
 		break;
 	}
 
 	free(lc);
 }
 
+/* Log a cell. */
 void
 layout_print_cell(struct layout_cell *lc, const char *hdr, u_int n)
 {
 	struct layout_cell	*lcchild;
 	const char		*type;
 
+	if (lc == NULL)
+		return;
+
 	switch (lc->type) {
 	case LAYOUT_LEFTRIGHT:
 		type = "LEFTRIGHT";
@@ -105,6 +128,9 @@ layout_print_cell(struct layout_cell *lc, const char *hdr, u_int n)
 	case LAYOUT_TOPBOTTOM:
 		type = "TOPBOTTOM";
 		break;
+	case LAYOUT_FLOATING:
+		type = "FLOATING";
+		break;
 	case LAYOUT_WINDOWPANE:
 		type = "WINDOWPANE";
 		break;
@@ -112,12 +138,13 @@ layout_print_cell(struct layout_cell *lc, const char *hdr, u_int n)
 		type = "UNKNOWN";
 		break;
 	}
-	log_debug("%s:%*s%p type %s [parent %p] wp=%p [%u,%u %ux%u]", hdr, n,
+	log_debug("%s:%*s%p type %s [parent %p] wp=%p [%d,%d %ux%u]", hdr, n,
 	    " ", lc, type, lc->parent, lc->wp, lc->xoff, lc->yoff, lc->sx,
 	    lc->sy);
 	switch (lc->type) {
 	case LAYOUT_LEFTRIGHT:
 	case LAYOUT_TOPBOTTOM:
+	case LAYOUT_FLOATING:
 		TAILQ_FOREACH(lcchild, &lc->cells, entry)
 		    	layout_print_cell(lcchild, hdr, n + 1);
 		break;
@@ -126,14 +153,17 @@ layout_print_cell(struct layout_cell *lc, const char *hdr, u_int n)
 	}
 }
 
+/* Search for a cell by the border position. */
 struct layout_cell *
 layout_search_by_border(struct layout_cell *lc, u_int x, u_int y)
 {
 	struct layout_cell	*lcchild, *last = NULL;
 
 	TAILQ_FOREACH(lcchild, &lc->cells, entry) {
-		if (x >= lcchild->xoff && x < lcchild->xoff + lcchild->sx &&
-		    y >= lcchild->yoff && y < lcchild->yoff + lcchild->sy) {
+		if ((int)x >= lcchild->xoff &&
+		    (int)x < lcchild->xoff + (int)lcchild->sx &&
+		    (int)y >= lcchild->yoff &&
+		    (int)y < lcchild->yoff + (int)lcchild->sy) {
 			/* Inside the cell - recurse. */
 			return (layout_search_by_border(lcchild, x, y));
 		}
@@ -145,14 +175,17 @@ layout_search_by_border(struct layout_cell *lc, u_int x, u_int y)
 
 		switch (lc->type) {
 		case LAYOUT_LEFTRIGHT:
-			if (x < lcchild->xoff && x >= last->xoff + last->sx)
+			if ((int)x < lcchild->xoff &&
+			    (int)x >= last->xoff + (int)last->sx)
 				return (last);
 			break;
 		case LAYOUT_TOPBOTTOM:
-			if (y < lcchild->yoff && y >= last->yoff + last->sy)
+			if ((int)y < lcchild->yoff &&
+			    (int)y >= last->yoff + (int)last->sy)
 				return (last);
 			break;
 		case LAYOUT_WINDOWPANE:
+		case LAYOUT_FLOATING:
 			break;
 		}
 
@@ -162,9 +195,9 @@ layout_search_by_border(struct layout_cell *lc, u_int x, u_int y)
 	return (NULL);
 }
 
+/* Set cell size. */
 void
-layout_set_size(struct layout_cell *lc, u_int sx, u_int sy, u_int xoff,
-    u_int yoff)
+layout_set_size(struct layout_cell *lc, u_int sx, u_int sy, int xoff, int yoff)
 {
 	lc->sx = sx;
 	lc->sy = sy;
@@ -173,6 +206,7 @@ layout_set_size(struct layout_cell *lc, u_int sx, u_int sy, u_int xoff,
 	lc->yoff = yoff;
 }
 
+/* Make a cell a leaf cell. */
 void
 layout_make_leaf(struct layout_cell *lc, struct window_pane *wp)
 {
@@ -184,6 +218,7 @@ layout_make_leaf(struct layout_cell *lc, struct window_pane *wp)
 	lc->wp = wp;
 }
 
+/* Make a cell a node cell. */
 void
 layout_make_node(struct layout_cell *lc, enum layout_type type)
 {
@@ -203,7 +238,7 @@ static void
 layout_fix_offsets1(struct layout_cell *lc)
 {
 	struct layout_cell	*lcchild;
-	u_int			 xoff, yoff;
+	int			 xoff, yoff;
 
 	if (lc->type == LAYOUT_LEFTRIGHT) {
 		xoff = lc->xoff;
@@ -246,6 +281,8 @@ layout_cell_is_top(struct window *w, struct layout_cell *lc)
 
 	while (lc != w->layout_root) {
 		next = lc->parent;
+		if (next == NULL)
+			return (0);
 		if (next->type == LAYOUT_TOPBOTTOM &&
 		    lc != TAILQ_FIRST(&next->cells))
 			return (0);
@@ -262,6 +299,8 @@ layout_cell_is_bottom(struct window *w, struct layout_cell *lc)
 
 	while (lc != w->layout_root) {
 		next = lc->parent;
+		if (next == NULL)
+			return (0);
 		if (next->type == LAYOUT_TOPBOTTOM &&
 		    lc != TAILQ_LAST(&next->cells, layout_cells))
 			return (0);
@@ -307,7 +346,8 @@ layout_fix_panes(struct window *w, struct window_pane *skip)
 		sx = lc->sx;
 		sy = lc->sy;
 
-		if (layout_add_horizontal_border(w, lc, status)) {
+		if ((~wp->flags & PANE_FLOATING) &&
+		    layout_add_horizontal_border(w, lc, status)) {
 			if (status == PANE_STATUS_TOP)
 				wp->yoff++;
 			sy--;
@@ -346,14 +386,14 @@ u_int
 layout_count_cells(struct layout_cell *lc)
 {
 	struct layout_cell	*lcchild;
-	u_int			 count;
+	u_int			 count = 0;
 
 	switch (lc->type) {
 	case LAYOUT_WINDOWPANE:
 		return (1);
 	case LAYOUT_LEFTRIGHT:
 	case LAYOUT_TOPBOTTOM:
-		count = 0;
+	case LAYOUT_FLOATING:
 		TAILQ_FOREACH(lcchild, &lc->cells, entry)
 			count += layout_count_cells(lcchild);
 		return (count);
@@ -470,13 +510,22 @@ layout_destroy_cell(struct window *w, struct layout_cell *lc,
 	struct layout_cell     *lcother, *lcparent;
 
 	/*
-	 * If no parent, this is the last pane so window close is imminent and
-	 * there is no need to resize anything.
+	 * If no parent, this is either a floating pane or the last
+	 * pane so window close is imminent and there is no need to
+	 * resize anything.
 	 */
 	lcparent = lc->parent;
 	if (lcparent == NULL) {
+		if (lc->wp != NULL && ~lc->wp->flags & PANE_FLOATING)
+			*lcroot = NULL;
+		layout_free_cell(lc);
+		return;
+	}
+
+	/* A floating cell need only be removed from the parent. */
+	if (lcparent->type == LAYOUT_FLOATING) {
+		TAILQ_REMOVE(&lcparent->cells, lc, entry);
 		layout_free_cell(lc);
-		*lcroot = NULL;
 		return;
 	}
 
@@ -499,12 +548,13 @@ layout_destroy_cell(struct window *w, struct layout_cell *lc,
 	 * replace it by that cell.
 	 */
 	lc = TAILQ_FIRST(&lcparent->cells);
-	if (TAILQ_NEXT(lc, entry) == NULL) {
+	if (lc != NULL && TAILQ_NEXT(lc, entry) == NULL) {
 		TAILQ_REMOVE(&lcparent->cells, lc, entry);
 
 		lc->parent = lcparent->parent;
 		if (lc->parent == NULL) {
-			lc->xoff = 0; lc->yoff = 0;
+			lc->xoff = 0;
+			lc->yoff = 0;
 			*lcroot = lc;
 		} else
 			TAILQ_REPLACE(&lc->parent->cells, lcparent, lc, entry);
@@ -513,6 +563,7 @@ layout_destroy_cell(struct window *w, struct layout_cell *lc,
 	}
 }
 
+/* Initialize layout for pane. */
 void
 layout_init(struct window *w, struct window_pane *wp)
 {
@@ -524,6 +575,7 @@ layout_init(struct window *w, struct window_pane *wp)
 	layout_fix_panes(w, NULL);
 }
 
+/* Free layout for pane. */
 void
 layout_free(struct window *w)
 {
@@ -741,7 +793,7 @@ layout_resize_pane_shrink(struct window *w, struct layout_cell *lc,
 	return (size);
 }
 
-/* Assign window pane to newly split cell. */
+/* Assign window pane to new cell. */
 void
 layout_assign_pane(struct layout_cell *lc, struct window_pane *wp,
     int do_not_resize)
@@ -1085,6 +1137,9 @@ layout_close_pane(struct window_pane *wp)
 {
 	struct window	*w = wp->window;
 
+	if (wp->layout_cell == NULL)
+		return;
+
 	/* Remove the cell. */
 	layout_destroy_cell(w, wp->layout_cell, &w->layout_root);
 
diff --git a/log.c b/log.c
index ede6e257..98a03763 100644
--- a/log.c
+++ b/log.c
@@ -150,6 +150,7 @@ fatal(const char *msg, ...)
 	log_vwrite(msg, ap, tmp);
 	va_end(ap);
 
+	abort ();//XXX
 	exit(1);
 }
 
@@ -163,5 +164,6 @@ fatalx(const char *msg, ...)
 	log_vwrite(msg, ap, "fatal: ");
 	va_end(ap);
 
+	abort ();//XXX
 	exit(1);
 }
diff --git a/server-fn.c b/server-fn.c
index 6c4c9c61..585a01f9 100644
--- a/server-fn.c
+++ b/server-fn.c
@@ -185,7 +185,7 @@ server_kill_pane(struct window_pane *wp)
 {
 	struct window	*w = wp->window;
 
-	if (window_count_panes(w) == 1) {
+	if (window_count_panes(w, 1) == 1) {
 		server_kill_window(w, 1);
 		recalculate_sizes();
 	} else {
diff --git a/tmux.h b/tmux.h
index 2c034b8e..2209732e 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1302,9 +1302,11 @@ struct window_pane {
 
 	TAILQ_ENTRY(window_pane) entry;  /* link in list of all panes */
 	TAILQ_ENTRY(window_pane) sentry; /* link in list of last visited */
+        TAILQ_ENTRY(window_pane) zentry; /* z-index link in list of all panes */
 	RB_ENTRY(window_pane) tree_entry;
 };
 TAILQ_HEAD(window_panes, window_pane);
+TAILQ_HEAD(window_panes_zindex, window_pane);
 RB_HEAD(window_pane_tree, window_pane);
 
 /* Window structure. */
@@ -1324,6 +1326,7 @@ struct window {
 
 	struct window_pane	*active;
 	struct window_panes 	 last_panes;
+	struct window_panes      z_index;
 	struct window_panes	 panes;
 
 	int			 lastlayout;
@@ -1417,6 +1420,7 @@ TAILQ_HEAD(winlink_stack, winlink);
 enum layout_type {
 	LAYOUT_LEFTRIGHT,
 	LAYOUT_TOPBOTTOM,
+	LAYOUT_FLOATING,
 	LAYOUT_WINDOWPANE
 };
 
@@ -1432,8 +1436,8 @@ struct layout_cell {
 	u_int		 sx;
 	u_int		 sy;
 
-	u_int		 xoff;
-	u_int		 yoff;
+	int		 xoff;
+	int		 yoff;
 
 	struct window_pane *wp;
 	struct layout_cells cells;
@@ -1710,10 +1714,10 @@ struct tty_ctx {
 	u_int			 orlower;
 
 	/* Target region (usually pane) offset and size. */
-	u_int			 xoff;
-	u_int			 yoff;
-	u_int			 rxoff;
-	u_int			 ryoff;
+	int			 xoff;
+	int			 yoff;
+	int			 rxoff;
+	int			 ryoff;
 	u_int			 sx;
 	u_int			 sy;
 
@@ -2284,6 +2288,7 @@ struct spawn_context {
 #define SPAWN_FULLSIZE 0x20
 #define SPAWN_EMPTY 0x40
 #define SPAWN_ZOOM 0x80
+#define SPAWN_FLOATING 0x100
 };
 
 /* Paste buffer. */
@@ -3362,7 +3367,7 @@ struct window_pane *window_pane_next_by_number(struct window *,
 struct window_pane *window_pane_previous_by_number(struct window *,
 			struct window_pane *, u_int);
 int		 window_pane_index(struct window_pane *, u_int *);
-u_int		 window_count_panes(struct window *);
+u_int		 window_count_panes(struct window *, int);
 void		 window_destroy_panes(struct window *);
 struct window_pane *window_pane_find_by_id_str(const char *);
 struct window_pane *window_pane_find_by_id(u_int);
@@ -3430,8 +3435,7 @@ void		 layout_destroy_cell(struct window *, struct layout_cell *,
 void		 layout_resize_layout(struct window *, struct layout_cell *,
 		     enum layout_type, int, int);
 struct layout_cell *layout_search_by_border(struct layout_cell *, u_int, u_int);
-void		 layout_set_size(struct layout_cell *, u_int, u_int, u_int,
-		     u_int);
+void             layout_set_size(struct layout_cell *, u_int, u_int, int, int);
 void		 layout_make_leaf(struct layout_cell *, struct window_pane *);
 void		 layout_make_node(struct layout_cell *, enum layout_type);
 void		 layout_fix_offsets(struct window *);
diff --git a/window-tree.c b/window-tree.c
index b58d5ed5..9b5269b7 100644
--- a/window-tree.c
+++ b/window-tree.c
@@ -387,7 +387,7 @@ window_tree_build(void *modedata, struct sort_criteria *sort_crit,
 		*tag = (uint64_t)data->fs.wl;
 		break;
 	case WINDOW_TREE_PANE:
-		if (window_count_panes(data->fs.wl->window) == 1)
+		if (window_count_panes(data->fs.wl->window, 1) == 1)
 			*tag = (uint64_t)data->fs.wl;
 		else
 			*tag = (uint64_t)data->fs.wp;
@@ -578,7 +578,7 @@ window_tree_draw_window(struct window_tree_modedata *data, struct session *s,
 	struct format_tree	*ft;
 	struct options		*oo;
 
-	total = window_count_panes(w);
+	total = window_count_panes(w, 1);
 
 	if (sx / total < 24) {
 		visible = sx / 24;
diff --git a/window.c b/window.c
index f554ee67..72ccb7cc 100644
--- a/window.c
+++ b/window.c
@@ -73,7 +73,7 @@ static struct window_pane *window_pane_create(struct window *, u_int, u_int,
 		    u_int);
 static void	window_pane_destroy(struct window_pane *);
 static void	window_pane_full_size_offset(struct window_pane *wp,
-		    u_int *xoff, u_int *yoff, u_int *sx, u_int *sy);
+		    int *xoff, int *yoff, u_int *sx, u_int *sy);
 
 RB_GENERATE(windows, window, entry, window_cmp);
 RB_GENERATE(winlinks, winlink, entry, winlink_cmp);
@@ -308,6 +308,7 @@ window_create(u_int sx, u_int sy, u_int xpixel, u_int ypixel)
 	w->flags = 0;
 
 	TAILQ_INIT(&w->panes);
+	TAILQ_INIT(&w->z_index);
 	TAILQ_INIT(&w->last_panes);
 	w->active = NULL;
 
@@ -523,6 +524,8 @@ window_set_active_pane(struct window *w, struct window_pane *wp, int notify)
 
 	if (wp == w->active)
 		return (0);
+	if (w->flags & WINDOW_ZOOMED)
+		window_unzoom(w, 1);
 	lastwp = w->active;
 
 	window_pane_stack_remove(&w->last_panes, wp);
@@ -665,7 +668,7 @@ window_zoom(struct window_pane *wp)
 	if (w->flags & WINDOW_ZOOMED)
 		return (-1);
 
-	if (window_count_panes(w) == 1)
+	if (window_count_panes(w, 1) == 1)
 		return (-1);
 
 	if (w->active != wp)
@@ -852,14 +855,15 @@ window_pane_index(struct window_pane *wp, u_int *i)
 }
 
 u_int
-window_count_panes(struct window *w)
+window_count_panes(struct window *w, int with_floating)
 {
 	struct window_pane	*wp;
-	u_int			 n;
+	u_int			 n = 0;
 
-	n = 0;
-	TAILQ_FOREACH(wp, &w->panes, entry)
-		n++;
+	TAILQ_FOREACH(wp, &w->panes, entry) {
+                if (with_floating || ~wp->flags & PANE_FLOATING)
+			n++;
+	}
 	return (n);
 }
 
@@ -1377,7 +1381,7 @@ window_pane_choose_best(struct window_pane **list, u_int size)
  * scrollbars if they were visible but not including the border(s).
  */
 static void
-window_pane_full_size_offset(struct window_pane *wp, u_int *xoff, u_int *yoff,
+window_pane_full_size_offset(struct window_pane *wp, int *xoff, int *yoff,
     u_int *sx, u_int *sy)
 {
 	struct window		*w = wp->window;
@@ -1411,9 +1415,9 @@ window_pane_find_up(struct window_pane *wp)
 {
 	struct window		*w;
 	struct window_pane	*next, *best, **list;
-	u_int			 edge, left, right, end, size;
-	int			 status, found;
-	u_int			 xoff, yoff, sx, sy;
+	int			 edge, left, right, end, status, found;
+	int			 xoff, yoff;
+	u_int			 size, sx, sy;
 
 	if (wp == NULL)
 		return (NULL);
@@ -1428,25 +1432,25 @@ window_pane_find_up(struct window_pane *wp)
 	edge = yoff;
 	if (status == PANE_STATUS_TOP) {
 		if (edge == 1)
-			edge = w->sy + 1;
+			edge = (int)w->sy + 1;
 	} else if (status == PANE_STATUS_BOTTOM) {
 		if (edge == 0)
-			edge = w->sy;
+			edge = (int)w->sy;
 	} else {
 		if (edge == 0)
-			edge = w->sy + 1;
+			edge = (int)w->sy + 1;
 	}
 
 	left = xoff;
-	right = xoff + sx;
+	right = xoff + (int)sx;
 
 	TAILQ_FOREACH(next, &w->panes, entry) {
 		window_pane_full_size_offset(next, &xoff, &yoff, &sx, &sy);
 		if (next == wp)
 			continue;
-		if (yoff + sy + 1 != edge)
+		if (yoff + (int)sy + 1 != edge)
 			continue;
-		end = xoff + sx - 1;
+		end = xoff + (int)sx - 1;
 
 		found = 0;
 		if (xoff < left && end > right)
@@ -1472,9 +1476,9 @@ window_pane_find_down(struct window_pane *wp)
 {
 	struct window		*w;
 	struct window_pane	*next, *best, **list;
-	u_int			 edge, left, right, end, size;
-	int			 status, found;
-	u_int			 xoff, yoff, sx, sy;
+	int			 edge, left, right, end, status, found;
+	int			 xoff, yoff;
+	u_int			 size, sx, sy;
 
 	if (wp == NULL)
 		return (NULL);
@@ -1486,20 +1490,20 @@ window_pane_find_down(struct window_pane *wp)
 
 	window_pane_full_size_offset(wp, &xoff, &yoff, &sx, &sy);
 
-	edge = yoff + sy + 1;
+	edge = yoff + (int)sy + 1;
 	if (status == PANE_STATUS_TOP) {
-		if (edge >= w->sy)
+		if (edge >= (int)w->sy)
 			edge = 1;
 	} else if (status == PANE_STATUS_BOTTOM) {
-		if (edge >= w->sy - 1)
+		if (edge >= (int)w->sy - 1)
 			edge = 0;
 	} else {
-		if (edge >= w->sy)
+		if (edge >= (int)w->sy)
 			edge = 0;
 	}
 
 	left = wp->xoff;
-	right = wp->xoff + wp->sx;
+	right = wp->xoff + (int)wp->sx;
 
 	TAILQ_FOREACH(next, &w->panes, entry) {
 		window_pane_full_size_offset(next, &xoff, &yoff, &sx, &sy);
@@ -1507,7 +1511,7 @@ window_pane_find_down(struct window_pane *wp)
 			continue;
 		if (yoff != edge)
 			continue;
-		end = xoff + sx - 1;
+		end = xoff + (int)sx - 1;
 
 		found = 0;
 		if (xoff < left && end > right)
@@ -1533,9 +1537,9 @@ window_pane_find_left(struct window_pane *wp)
 {
 	struct window		*w;
 	struct window_pane	*next, *best, **list;
-	u_int			 edge, top, bottom, end, size;
-	int			 found;
-	u_int			 xoff, yoff, sx, sy;
+	int			 edge, top, bottom, end, found;
+	int			 xoff, yoff;
+	u_int			 size, sx, sy;
 
 	if (wp == NULL)
 		return (NULL);
@@ -1548,18 +1552,18 @@ window_pane_find_left(struct window_pane *wp)
 
 	edge = xoff;
 	if (edge == 0)
-		edge = w->sx + 1;
+		edge = (int)w->sx + 1;
 
 	top = yoff;
-	bottom = yoff + sy;
+	bottom = yoff + (int)sy;
 
 	TAILQ_FOREACH(next, &w->panes, entry) {
 		window_pane_full_size_offset(next, &xoff, &yoff, &sx, &sy);
 		if (next == wp)
 			continue;
-		if (xoff + sx + 1 != edge)
+		if (xoff + (int)sx + 1 != edge)
 			continue;
-		end = yoff + sy - 1;
+		end = yoff + (int)sy - 1;
 
 		found = 0;
 		if (yoff < top && end > bottom)
@@ -1585,9 +1589,9 @@ window_pane_find_right(struct window_pane *wp)
 {
 	struct window		*w;
 	struct window_pane	*next, *best, **list;
-	u_int			 edge, top, bottom, end, size;
-	int			 found;
-	u_int			 xoff, yoff, sx, sy;
+	int			 edge, top, bottom, end, found;
+	int			 xoff, yoff;
+	u_int			 size, sx, sy;
 
 	if (wp == NULL)
 		return (NULL);
@@ -1598,12 +1602,12 @@ window_pane_find_right(struct window_pane *wp)
 
 	window_pane_full_size_offset(wp, &xoff, &yoff, &sx, &sy);
 
-	edge = xoff + sx + 1;
-	if (edge >= w->sx)
+	edge = xoff + (int)sx + 1;
+	if (edge >= (int)w->sx)
 		edge = 0;
 
 	top = wp->yoff;
-	bottom = wp->yoff + wp->sy;
+	bottom = wp->yoff + (int)wp->sy;
 
 	TAILQ_FOREACH(next, &w->panes, entry) {
 		window_pane_full_size_offset(next, &xoff, &yoff, &sx, &sy);
@@ -1611,7 +1615,7 @@ window_pane_find_right(struct window_pane *wp)
 			continue;
 		if (xoff != edge)
 			continue;
-		end = yoff + sy - 1;
+		end = yoff + (int)sy - 1;
 
 		found = 0;
 		if (yoff < top && end > bottom)
@@ -1631,6 +1635,7 @@ window_pane_find_right(struct window_pane *wp)
 	return (best);
 }
 
+/* Add window to stack. */
 void
 window_pane_stack_push(struct window_panes *stack, struct window_pane *wp)
 {
@@ -1641,6 +1646,7 @@ window_pane_stack_push(struct window_panes *stack, struct window_pane *wp)
 	}
 }
 
+/* Remove window from stack. */
 void
 window_pane_stack_remove(struct window_panes *stack, struct window_pane *wp)
 {