From 0ce3f20a2dc77719b81f300484e2e17625f8e069 Mon Sep 17 00:00:00 2001
From: Michael Grant <mgrant@grant.org>
Date: Thu, 1 Oct 2026 17:56:43 +0100
Subject: [PATCH] Hide the zoomed panes when a covered tiled pane is activated.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
---
 cmd-resize-pane.c                   | 12 ++++++++-
 cmd-rotate-window.c                 |  4 +--
 cmd-select-pane.c                   | 17 ++++++------
 cmd-switch-client.c                 |  2 +-
 regress/floating-pane-zoom-stack.sh | 21 ++++++++++++---
 regress/pane-hidden.sh              | 42 +++++++++++++++++++++++++++++
 regress/pane-ops.sh                 | 21 ++++++++++++---
 regress/pane-states.sh              | 31 ++++++++++++++++-----
 regress/window-ops.sh               | 10 +++++--
 window.c                            | 36 +++++++++++++++++++++----
 10 files changed, 164 insertions(+), 32 deletions(-)

diff --git a/cmd-resize-pane.c b/cmd-resize-pane.c
index d7f7ae445..6f04c2fae 100644
--- a/cmd-resize-pane.c
+++ b/cmd-resize-pane.c
@@ -77,8 +77,18 @@ cmd_resize_pane_desktop(struct window *w)
 			shown = 1;
 		}
 	}
-	if (shown)
+	if (shown) {
+		/* Do not leave the active pane covered by a pane just shown. */
+		if (!window_pane_is_visible(w->active)) {
+			TAILQ_FOREACH(wp, &w->z_index, zentry) {
+				if (window_pane_is_visible(wp))
+					break;
+			}
+			if (wp != NULL)
+				window_set_active_pane(w, wp, 1);
+		}
 		return;
+	}
 
 	TAILQ_FOREACH(wp, &w->panes, entry) {
 		if (wp == w->modal || (wp->flags & PANE_HIDDEN))
diff --git a/cmd-rotate-window.c b/cmd-rotate-window.c
index 3e112bbf2..c47814d85 100644
--- a/cmd-rotate-window.c
+++ b/cmd-rotate-window.c
@@ -121,10 +121,10 @@ cmd_rotate_window_exec(struct cmd *self, struct cmdq_item *item)
 
 	if (active != -1) {
 		wp = rotated[active];
-		window_set_active_pane(w, wp, 1);
-		cmd_find_from_winlink_pane(current, wl, wp, 0);
 		if (zwp != NULL)
 			window_zoom_move(zwp, wp);
+		window_set_active_pane(w, wp, 1);
+		cmd_find_from_winlink_pane(current, wl, wp, 0);
 	}
 	redraw_invalidate_scene(w);
 	server_redraw_window(w);
diff --git a/cmd-select-pane.c b/cmd-select-pane.c
index 6c9185a6c..5a1ff3d11 100644
--- a/cmd-select-pane.c
+++ b/cmd-select-pane.c
@@ -193,14 +193,15 @@ cmd_select_pane_exec(struct cmd *self, struct cmdq_item *item)
 			if (!visible && Zflag)
 				zwp = window_zoomed_pane(w);
 			window_redraw_active_switch(w, lastwp);
-			if (window_set_active_pane(w, lastwp, 1)) {
-				cmd_find_from_winlink(current, wl, 0);
-				cmd_select_pane_redraw(w);
-			}
 			if (zwp != NULL) {
 				window_zoom_move(zwp, lastwp);
 				server_redraw_window(w);
 			}
+			if (window_set_active_pane(w, lastwp, 1) ||
+			    zwp != NULL) {
+				cmd_find_from_winlink(current, wl, 0);
+				cmd_select_pane_redraw(w);
+			}
 		}
 		return (CMD_RETURN_NORMAL);
 	}
@@ -273,14 +274,14 @@ cmd_select_pane_exec(struct cmd *self, struct cmdq_item *item)
 	if (!visible && Zflag)
 		zwp = window_zoomed_pane(w);
 	window_redraw_active_switch(w, wp);
-	if (window_set_active_pane(w, wp, 1))
-		cmd_find_from_winlink_pane(current, wl, wp, 0);
-	cmdq_insert_hook(s, item, current, "after-select-pane");
-	cmd_select_pane_redraw(w);
 	if (zwp != NULL) {
 		window_zoom_move(zwp, wp);
 		server_redraw_window(w);
 	}
+	if (window_set_active_pane(w, wp, 1) || zwp != NULL)
+		cmd_find_from_winlink_pane(current, wl, wp, 0);
+	cmdq_insert_hook(s, item, current, "after-select-pane");
+	cmd_select_pane_redraw(w);
 
 	return (CMD_RETURN_NORMAL);
 }
diff --git a/cmd-switch-client.c b/cmd-switch-client.c
index 204725429..04c34785e 100644
--- a/cmd-switch-client.c
+++ b/cmd-switch-client.c
@@ -147,11 +147,11 @@ cmd_switch_client_exec(struct cmd *self, struct cmdq_item *item)
 			if (!visible && Zflag)
 				zwp = window_zoomed_pane(w);
 			window_redraw_active_switch(w, wp);
-			window_set_active_pane(w, wp, 1);
 			if (zwp != NULL) {
 				window_zoom_move(zwp, wp);
 				server_redraw_window(w);
 			}
+			window_set_active_pane(w, wp, 1);
 		}
 		if (wl != NULL) {
 			session_set_current(s, wl);
diff --git a/regress/floating-pane-zoom-stack.sh b/regress/floating-pane-zoom-stack.sh
index 0068cc6c4..945792e3f 100644
--- a/regress/floating-pane-zoom-stack.sh
+++ b/regress/floating-pane-zoom-stack.sh
@@ -144,17 +144,32 @@ zoomed "$Y" 1
 zoomed "$A" 1
 window_zoomed "$X" 1
 
-# Activating a tiled pane that is not zoomed unzooms every pane but the
-# floats stay floats.
+# Activating a tiled pane that is not zoomed hides the zoomed panes, as the
+# desktop does, and shows the tiles. They stay zoomed, and floats that are not
+# zoomed stay where they are.
 run select-pane -t "$B"
 check "$B" '#{pane_active}' 1
-for p in "$A" "$B" "$X" "$Y"; do
+for p in "$A" "$Y"; do
+	zoomed "$p" 1
+	check "$p" '#{pane_hidden_flag}' 1
+done
+for p in "$B" "$X"; do
 	zoomed "$p" 0
+	check "$p" '#{pane_hidden_flag}' 0
 done
 window_zoomed "$B" 0
 check "$X" '#{pane_floating_flag}' 1
 check "$Y" '#{pane_floating_flag}' 1
 
+# The desktop shows them again.
+run resize-pane -a -H -t "$A"
+for p in "$A" "$Y"; do
+	zoomed "$p" 1
+	check "$p" '#{pane_hidden_flag}' 0
+done
+window_zoomed "$B" 1
+run resize-pane -a -Z -t "$A"
+
 # Activating a tiled pane that is itself zoomed does not unzoom it.
 run resize-pane -Z -t "$A"
 run select-pane -t "$A"
diff --git a/regress/pane-hidden.sh b/regress/pane-hidden.sh
index bc89fbdcd..53d4e1e51 100644
--- a/regress/pane-hidden.sh
+++ b/regress/pane-hidden.sh
@@ -237,6 +237,48 @@ run resize-pane -a -H -t "$A"
 hidden "$A" 0
 hidden "$X" 0
 
+# Activating a tiled pane that is covered by zoomed panes hides them, as the
+# desktop does: they stay zoomed, the tiles are shown and the pane is active.
+reset
+C=$(run split-window -dPF '#{pane_id}') || exit 1
+run resize-pane -Z -t "$A"
+run resize-pane -Z -t "$B"
+run select-pane -t "$C"
+check "$C" '#{pane_active}' 1
+for p in "$A" "$B"; do
+	hidden "$p" 1
+	check "$p" '#{pane_zoomed_flag}' 1
+done
+hidden "$C" 0
+check "$C" '#{window_zoomed_flag}' 0
+# The last pane brings back the one that was zoomed.
+run select-pane -l
+check "$B" '#{pane_active}:#{pane_hidden_flag}:#{window_zoomed_flag}' '1:0:1'
+# The desktop shows the others, and the active pane is not left covered.
+run select-pane -t "$C"
+run resize-pane -a -H -t "$A"
+for p in "$A" "$B"; do
+	hidden "$p" 0
+done
+check "$A" '#{window_zoomed_flag}' 1
+visible=$(run list-panes -F '#{pane_active}#{pane_zoomed_flag}' | grep -c '^11$')
+[ "$visible" = 1 ] || fail "active pane is covered after the desktop"
+
+# select-pane -Z moves the zoom to a covered tiled pane without hiding the old
+# one, and so do last-pane -Z and rotate-window -Z.
+reset
+run resize-pane -Z -t "$A"
+run select-pane -Z -t "$B"
+check "$B" '#{pane_zoomed_flag}:#{pane_active}' '1:1'
+check "$A" '#{pane_zoomed_flag}:#{pane_hidden_flag}' '0:0'
+run select-pane -Z -t "$A"
+run select-pane -Z -l
+check "$B" '#{pane_zoomed_flag}:#{pane_hidden_flag}' '1:0'
+check "$A" '#{pane_zoomed_flag}:#{pane_hidden_flag}' '0:0'
+run rotate-window -Z
+check "$A" '#{pane_hidden_flag}' 0
+check "$B" '#{pane_hidden_flag}' 0
+
 # Floating and tiling a hidden pane keeps it hidden.
 reset
 run resize-pane -H -t "$B"
diff --git a/regress/pane-ops.sh b/regress/pane-ops.sh
index 60696234a..85d6d667b 100644
--- a/regress/pane-ops.sh
+++ b/regress/pane-ops.sh
@@ -320,7 +320,7 @@ check_ok resize-pane -Z -t "$p0"
 check_fmt "$p0" '#{window_zoomed_flag}' '0'
 
 # Splitting while zoomed with -d leaves the zoom alone; without -d the new
-# pane is active and covered, so selecting it unzooms.
+# pane is active and covered, so selecting it hides the zoomed pane.
 check_ok resize-pane -Z -t "$p0"
 check_fmt 'P:0' '#{window_zoomed_flag}' '1'
 check_ok split-window -d -v -t "$p0"
@@ -334,16 +334,25 @@ check_fmt 'P:0' '#{window_zoomed_flag}' '0'
 check_ok resize-pane -Z -t "$p0"
 check_ok split-window -v -t "$p0"
 check_fmt 'P:0' '#{window_zoomed_flag}' '0'
+check_fmt "$p0" '#{pane_zoomed_flag}:#{pane_hidden_flag}' '1:1'
 p6=$($TMUX display-message -p -t P:0 '#{pane_id}')
 check_ok kill-pane -t "$p6"
+check_ok resize-pane -a -H -t "$p0"
+check_ok resize-pane -a -Z -t "$p0"
 
 # Zoom and unzoom preserve the exact tiled layout. Selecting another pane
-# without -Z unzooms, while -Z transfers zoom to the selected pane.
+# without -Z hides the zoomed pane until the desktop shows it, while -Z
+# transfers zoom to the selected pane.
 layout=$(pane_layout P:0)
 check_ok select-pane -t "$p0"
 check_ok resize-pane -Z -t "$p0"
 check_ok select-pane -t "$p2"
 check_fmt "$p2" '#{window_zoomed_flag}:#{pane_active}' '0:1'
+check_fmt "$p0" '#{pane_zoomed_flag}:#{pane_hidden_flag}' '1:1'
+check_ok resize-pane -a -H -t "$p0"
+check_fmt "$p0" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
+	'1:1:1'
+check_ok resize-pane -a -Z -t "$p0"
 check_layout P:0 "$layout"
 
 check_ok select-pane -t "$p0"
@@ -355,7 +364,7 @@ check_ok resize-pane -Z -t "$p2"
 check_layout P:0 "$layout"
 
 # Directional selection temporarily restores the full layout to find its
-# neighbour, then follows the same unzoom or -Z transfer rules.
+# neighbour, then follows the same hide or -Z transfer rules.
 check_ok select-pane -t "$p0"
 check_ok resize-pane -Z -t "$p0"
 check_ok select-pane -t "$p0"
@@ -363,6 +372,9 @@ check_fmt "$p0" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
 	'1:1:1'
 check_ok select-pane -D -t "$p0"
 check_fmt "$p2" '#{window_zoomed_flag}:#{pane_active}' '0:1'
+check_fmt "$p0" '#{pane_zoomed_flag}:#{pane_hidden_flag}' '1:1'
+check_ok resize-pane -a -H -t "$p0"
+check_ok resize-pane -a -Z -t "$p0"
 
 check_ok select-pane -t "$p0"
 check_ok resize-pane -Z -t "$p0"
@@ -379,6 +391,9 @@ check_ok resize-pane -Z -t "$p2"
 check_ok select-pane -l -t P:0
 check_fmt "$p0" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
 	'0:0:1'
+check_fmt "$p2" '#{pane_zoomed_flag}:#{pane_hidden_flag}' '1:1'
+check_ok resize-pane -a -H -t "$p0"
+check_ok resize-pane -a -Z -t "$p0"
 
 check_ok select-pane -t "$p0"
 check_ok select-pane -t "$p2"
diff --git a/regress/pane-states.sh b/regress/pane-states.sh
index 43780c503..eeffbdf8f 100644
--- a/regress/pane-states.sh
+++ b/regress/pane-states.sh
@@ -93,6 +93,21 @@ function noZoom(    i)
 			fail("pane " aid[i] " is still zoomed")
 	}
 }
+function hideZoomed(t,    i, id, want)
+{
+	sameZ("")
+	for (i = 1; i <= nb; i++) {
+		id = bid[i]
+		if (id == t || !(id in ina))
+			continue
+		want = (bH[id] || bZ[id]) ? 1 : 0
+		if (aH[id] != want)
+			fail("pane " id " zoomed " bZ[id] " hidden " bH[id] \
+			    " became hidden " aH[id])
+	}
+	if (aH[t])
+		fail("pane " t " is still hidden")
+}
 function covered(t,    i, q)
 {
 	if (bF[t] || bZ[t])
@@ -177,8 +192,9 @@ END {
 	if (op == "select") {
 		if (aA[T] != 1) fail("not active")
 		if (aH[T]) fail("still hidden")
-		if (covered(T)) noZoom(); else sameZ("")
-		sameF(""); sameH(T)
+		if (covered(T)) hideZoomed(T)
+		else { sameZ(""); sameH(T) }
+		sameF("")
 	} else if (op == "zoom") {
 		sameF("")
 		if (bZ[T]) {
@@ -195,12 +211,12 @@ END {
 		if (bH[T]) {
 			if (aH[T]) fail("not shown")
 			if (aA[T] != 1) fail("not active when shown")
-			if (covered(T)) noZoom(); else sameZ("")
+			if (covered(T)) hideZoomed(T)
+			else { sameZ(""); sameH(T) }
 		} else {
 			if (!aH[T]) fail("not hidden")
-			sameZ("")
+			sameZ(""); sameH(T)
 		}
-		sameH(T)
 	} else if (op == "desktop") {
 		sameF(""); sameZ("")
 		for (i = 1; i <= nb; i++) {
@@ -267,11 +283,12 @@ END {
 		sameF(""); sameH(""); noZoom()
 	} else {
 		# Moving around or changing layout: floating panes stay floating
-		# and nothing is hidden.
+		# and only a zoomed pane is hidden, when a covered pane is made
+		# active.
 		sameF("")
 		for (i = 1; i <= nb; i++) {
 			id = bid[i]
-			if (id in ina && aH[id] > bH[id])
+			if (id in ina && aH[id] > bH[id] && !bZ[id])
 				fail("pane " id " was hidden by this")
 		}
 	}
diff --git a/regress/window-ops.sh b/regress/window-ops.sh
index c1bbce674..b1704de18 100644
--- a/regress/window-ops.sh
+++ b/regress/window-ops.sh
@@ -337,14 +337,20 @@ check_fmt 'R:0' '#{pane_index}:#{pane_id}' "0:$p1"
 check_ok rotate-window -D -t R:0
 check_fmt 'R:0' '#{pane_index}:#{pane_id}' "0:$p0"
 
-# Rotation without -Z unzooms. With -Z it preserves zoom and transfers it to
-# the pane which arrives at the active position.
+# Rotation without -Z hides the zoomed pane until the desktop shows it. With -Z
+# it preserves zoom and transfers it to the pane which arrives at the active
+# position.
 layout=$($TMUX display-message -p -t R:0 '#{window_layout}')
 check_ok resize-pane -Z -t "$p0"
 check_ok rotate-window -U -t R:0
 check_fmt "$p1" '#{window_zoomed_flag}:#{pane_zoomed_flag}:#{pane_active}' \
 	'0:0:1'
+check_fmt "$p0" '#{pane_zoomed_flag}:#{pane_hidden_flag}' '1:1'
+check_ok resize-pane -a -H -t "$p0"
+check_ok resize-pane -a -Z -t "$p0"
 check_ok rotate-window -D -t R:0
+check_ok select-pane -t "$p1"
+check_ok select-pane -t "$p0"
 check_fmt 'R:0' '#{window_layout}' "$layout"
 
 check_ok resize-pane -Z -t "$p0"
diff --git a/window.c b/window.c
index d1eb4ee13..7fd5398cf 100644
--- a/window.c
+++ b/window.c
@@ -75,6 +75,8 @@ static void	window_pane_free(struct window_pane *);
 static void	window_pane_scrollbar_timer(int, short, void *);
 static int	window_activate_pane(struct window *, struct window_pane *, int,
 		    int);
+static void	window_hide_one(struct window_pane *, int);
+static void	window_hide_zoomed(struct window *);
 static void	window_pane_full_size_offset(struct window_pane *, int *, int *,
 		    u_int *, u_int *);
 
@@ -775,14 +777,14 @@ window_activate_pane(struct window *w, struct window_pane *wp, int notify,
 		return (0);
 	if (!window_pane_is_visible(wp)) {
 		/*
-		 * The pane is covered by a zoomed pane. A tiled pane that is
-		 * not zoomed can only be reached by unzooming (any floats
-		 * stay); anything else can be raised above the zoom.
+		 * The pane is covered by a zoomed pane. Raise it above the zoom
+		 * if it can be, otherwise (a tiled pane that is not zoomed) hide
+		 * the zoomed panes, as the desktop does, to show the tiles.
 		 */
 		if (window_pane_is_raised(wp))
 			window_raise_pane(wp);
 		else
-			window_unzoom(w, 1);
+			window_hide_zoomed(w);
 	} else if (raise) {
 		/* Raise the pane if the option says to. */
 		switch (options_get_number(w->options, "pane-raise-on-focus")) {
@@ -1041,6 +1043,30 @@ window_count_tiled_siblings(struct layout_cell *lc)
  */
 void
 window_hide_pane(struct window_pane *wp)
+{
+	window_hide_one(wp, 1);
+}
+
+/*
+ * Hide every zoomed pane that is not hidden, marking them as the desktop does so
+ * that it shows them again. The focus is left for the caller to move.
+ */
+static void
+window_hide_zoomed(struct window *w)
+{
+	struct window_pane	*wp;
+
+	TAILQ_FOREACH(wp, &w->panes, entry) {
+		if ((wp->flags & PANE_ZOOMED) && (~wp->flags & PANE_HIDDEN)) {
+			window_hide_one(wp, 0);
+			wp->flags |= PANE_HIDDENALL;
+		}
+	}
+}
+
+/* Hide a pane, moving the focus away from it if it is active and asked to. */
+static void
+window_hide_one(struct window_pane *wp, int refocus)
 {
 	struct window		*w = wp->window;
 	struct layout_cell	*lc = wp->layout_cell;
@@ -1068,7 +1094,7 @@ window_hide_pane(struct window_pane *wp)
 	layout_fix_panes(w, NULL);
 
 	/* Move the focus to the last used pane or the top one that is seen. */
-	if (wp == w->active) {
+	if (refocus && wp == w->active) {
 		TAILQ_FOREACH(wp1, &w->last_panes, sentry) {
 			if (wp1 != wp && window_pane_is_visible(wp1))
 				break;