The target validity check used window_pane_visible but that may be false

if the pane is zoomed, so instead add a new function to just check if
the pane is actually on screen (most commands still want to accept panes
invisible by zoom). Also reject panes outside the window for various
special targets. Problem reported by Sean Haugh.

cmd-find.c

@@ -658,7 +658,7 @@ cmd_find_get_pane(struct cmd_find_state *fs, const char *pane)
 	/* Check for pane ids starting with %. */
 	if (*pane == '%') {
 		fs->wp = window_pane_find_by_id_str(pane);
-		if (fs->wp == NULL)
+		if (fs->wp == NULL || window_pane_outside(fs->wp))
 			return (-1);
 		fs->w = fs->wp->window;
 		return (cmd_find_best_session_with_window(fs));
@@ -695,7 +695,7 @@ cmd_find_get_pane_with_session(struct cmd_find_state *fs, const char *pane)
 	/* Check for pane ids starting with %. */
 	if (*pane == '%') {
 		fs->wp = window_pane_find_by_id_str(pane);
-		if (fs->wp == NULL)
+		if (fs->wp == NULL || window_pane_outside(fs->wp))
 			return (-1);
 		fs->w = fs->wp->window;
 		return (cmd_find_best_winlink_with_window(fs));
@@ -727,7 +727,9 @@ cmd_find_get_pane_with_window(struct cmd_find_state *fs, const char *pane)
 	/* Check for pane ids starting with %. */
 	if (*pane == '%') {
 		fs->wp = window_pane_find_by_id_str(pane);
-		if (fs->wp == NULL || fs->wp->window != fs->w)
+		if (fs->wp == NULL || window_pane_outside(fs->wp))
+			return (-1);
+		if (fs->wp->window != fs->w)
 			return (-1);
 		return (0);
 	}
@@ -737,25 +739,27 @@ cmd_find_get_pane_with_window(struct cmd_find_state *fs, const char *pane)
 		if (fs->w->last == NULL)
 			return (-1);
 		fs->wp = fs->w->last;
+		if (fs->wp == NULL || window_pane_outside(fs->wp))
+			return (-1);
 		return (0);
 	} else if (strcmp(pane, "{up-of}") == 0) {
 		fs->wp = window_pane_find_up(fs->w->active);
-		if (fs->wp == NULL)
+		if (fs->wp == NULL || window_pane_outside(fs->wp))
 			return (-1);
 		return (0);
 	} else if (strcmp(pane, "{down-of}") == 0) {
 		fs->wp = window_pane_find_down(fs->w->active);
-		if (fs->wp == NULL)
+		if (fs->wp == NULL || window_pane_outside(fs->wp))
 			return (-1);
 		return (0);
 	} else if (strcmp(pane, "{left-of}") == 0) {
 		fs->wp = window_pane_find_left(fs->w->active);
-		if (fs->wp == NULL)
+		if (fs->wp == NULL || window_pane_outside(fs->wp))
 			return (-1);
 		return (0);
 	} else if (strcmp(pane, "{right-of}") == 0) {
 		fs->wp = window_pane_find_right(fs->w->active);
-		if (fs->wp == NULL)
+		if (fs->wp == NULL || window_pane_outside(fs->wp))
 			return (-1);
 		return (0);
 	}
@@ -771,7 +775,7 @@ cmd_find_get_pane_with_window(struct cmd_find_state *fs, const char *pane)
 			fs->wp = window_pane_next_by_number(fs->w, wp, n);
 		else
 			fs->wp = window_pane_previous_by_number(fs->w, wp, n);
-		if (fs->wp != NULL)
+		if (fs->wp != NULL && !window_pane_outside(fs->wp))
 			return (0);
 	}
 
@@ -779,13 +783,13 @@ cmd_find_get_pane_with_window(struct cmd_find_state *fs, const char *pane)
 	idx = strtonum(pane, 0, INT_MAX, &errstr);
 	if (errstr == NULL) {
 		fs->wp = window_pane_at_index(fs->w, idx);
-		if (fs->wp != NULL)
+		if (fs->wp != NULL && !window_pane_outside(fs->wp))
 			return (0);
 	}
 
 	/* Try as a description. */
 	fs->wp = window_find_string(fs->w, pane);
-	if (fs->wp != NULL)
+	if (fs->wp != NULL && !window_pane_outside(fs->wp))
 		return (0);
 
 	return (-1);
@@ -837,7 +841,7 @@ cmd_find_valid_state(struct cmd_find_state *fs)
 
 	if (!window_has_pane(fs->w, fs->wp))
 		return (0);
-	return (window_pane_visible(fs->wp));
+	return (!window_pane_outside(fs->wp));
 }
 
 /* Copy a state. */
@@ -945,6 +949,8 @@ cmd_find_from_pane(struct cmd_find_state *fs, struct window_pane *wp)
 {
 	if (cmd_find_from_window(fs, wp->window) != 0)
 		return (-1);
+	if (window_pane_outside(wp))
+		return (-1);
 	fs->wp = wp;
 
 	cmd_find_log_state(__func__, fs);
@@ -1012,7 +1018,7 @@ cmd_find_target(struct cmd_find_state *fs, struct cmd_find_state *current,
 		switch (type) {
 		case CMD_FIND_PANE:
 			fs->wp = cmd_mouse_pane(m, &fs->s, &fs->wl);
-			if (fs->wp != NULL)
+			if (fs->wp != NULL && !window_pane_outside(fs->wp))
 				fs->w = fs->wl->window;
 			break;
 		case CMD_FIND_WINDOW:

cmd-select-pane.c

@@ -63,7 +63,6 @@ cmd_select_pane_exec(struct cmd *self, struct cmdq_item *item)
 	const char		*style;
 
 	if (self->entry == &cmd_last_pane_entry || args_has(args, 'l')) {
-
 		if (wl->window->last == NULL) {
 			cmdq_error(item, "no last pane");
 			return (CMD_RETURN_ERROR);

tmux.h

@@ -2126,6 +2126,7 @@ int		 window_pane_set_mode(struct window_pane *,
 void		 window_pane_reset_mode(struct window_pane *);
 void		 window_pane_key(struct window_pane *, struct client *,
 		     struct session *, key_code, struct mouse_event *);
+int		 window_pane_outside(struct window_pane *);
 int		 window_pane_visible(struct window_pane *);
 char		*window_pane_search(struct window_pane *, const char *,
 		     u_int *);

window.c

@@ -1185,17 +1185,23 @@ window_pane_key(struct window_pane *wp, struct client *c, struct session *s,
 }
 
 int
-window_pane_visible(struct window_pane *wp)
+window_pane_outside(struct window_pane *wp)
 {
 	struct window	*w = wp->window;
 
+	if (wp->xoff >= w->sx || wp->yoff >= w->sy)
+		return (1);
+	if (wp->xoff + wp->sx > w->sx || wp->yoff + wp->sy > w->sy)
+		return (1);
+	return (0);
+}
+
+int
+window_pane_visible(struct window_pane *wp)
+{
 	if (wp->layout_cell == NULL)
 		return (0);
-	if (wp->xoff >= w->sx || wp->yoff >= w->sy)
-		return (0);
-	if (wp->xoff + wp->sx > w->sx || wp->yoff + wp->sy > w->sy)
-		return (0);
-	return (1);
+	return (!window_pane_outside(wp));
 }
 
 char *