Do not show the cursor for a hidden active pane.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

regress/hidden-pane-cursor.sh

@@ -0,0 +1,70 @@
+#!/bin/sh
+
+# The cursor must not be drawn for a hidden active pane, for example in the
+# middle of an empty desktop after "show desktop" with every other pane hidden.
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -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
+}
+
+# cursor EXPECTED
+#
+# Check whether the outer pane showing the inner client has a visible cursor.
+cursor()
+{
+	i=0
+	while [ "$i" -lt 30 ]; do
+		got=$($TMUX2 display-message -p -t "$OUTER" '#{cursor_flag}')
+		[ "$got" = "$1" ] && return 0
+		sleep 0.2
+		i=$((i + 1))
+	done
+	fail "cursor_flag: got '$got', expected '$1'"
+}
+
+cleanup
+
+$TMUX new-session -d -s inner -x 60 -y 12 'cat' || exit 1
+a=$($TMUX display-message -p '#{pane_id}') || exit 1
+b=$($TMUX split-window -dPF '#{pane_id}' 'cat') || exit 1
+f=$($TMUX new-pane -dPF '#{pane_id}' -x 20 -y 4 -X 20 -Y 2 'cat') || exit 1
+
+$TMUX2 new-session -d -x 60 -y 12 "$TMUX attach -t inner" || exit 1
+sleep 1
+OUTER=$($TMUX2 list-panes -F '#{pane_id}' | head -1)
+[ -n "$OUTER" ] || fail "No outer pane."
+
+# A zoomed pane with a floating pane over it and another tiled pane: hide
+# everything above the layout, then the remaining tiled pane.
+$TMUX resize-pane -Z -t "$a" || fail "zoom failed"
+$TMUX select-pane -t "$f" || fail "select failed"
+cursor 1
+$TMUX resize-pane -a -H || fail "show desktop failed"
+$TMUX resize-pane -H -t "$b" || fail "hide failed"
+for p in "$a" "$b" "$f"; do
+	[ "$($TMUX display-message -p -t "$p" '#{pane_hidden_flag}')" = 1 ] ||
+	    fail "$p is not hidden"
+done
+cursor 0
+
+# Showing a pane brings the cursor back.
+$TMUX select-pane -t "$b" || fail "select failed"
+cursor 1
+
+cleanup
+exit 0

server-client.c

@@ -2121,6 +2121,10 @@ server_client_reset_state(struct client *c)
 					cy += status_line_size(c);
 			}
 
+			/* A hidden pane has no cursor. */
+			if (!window_pane_is_visible(wp))
+				cursor = 0;
+
 			if (!cursor)
 				mode &= ~MODE_CURSOR;
 		}