sway: extensions: only unlock if lock_surfaces.length == 0

When destroying lock surfaces, we really should only unlock a
desktop_shell if the set of lock surfaces has dropped to zero (since
callers need to do a set_lock_surface for every output).

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>

sway/extensions.c

@@ -65,10 +65,12 @@ void lock_surface_destructor(struct wl_resource *resource) {
 		if (surface == resource) {
 			list_del(desktop_shell.lock_surfaces, i);
 			arrange_windows(&root_container, -1, -1);
-			desktop_shell.is_locked = false;
 			break;
 		}
 	}
+	if (desktop_shell.lock_surfaces->length == 0) {
+		desktop_shell.is_locked = false;
+	}
 }
 
 static void set_background(struct wl_client *client, struct wl_resource *resource,