Don't restore vertical-tabs panel when feature is disabled

app/src/workspace/view.rs

@@ -3796,9 +3796,10 @@ impl Workspace {
             NewWorkspaceSource::Restored {
                 window_snapshot, ..
             } => {
-                if should_default_open
-                    && *TabSettings::as_ref(ctx).show_vertical_tab_panel_in_restored_windows
-                {
+                if !should_default_open {
+                    // Stale "panel open" snapshot would leave a click-eating dismiss underlay (#9505).
+                    false
+                } else if *TabSettings::as_ref(ctx).show_vertical_tab_panel_in_restored_windows {
                     true
                 } else {
                     window_snapshot.vertical_tabs_panel_open

app/src/workspace/view_tests.rs

@@ -2412,6 +2412,41 @@ fn test_vertical_tabs_panel_restored_open_when_show_in_restored_windows_enabled(
     });
 }
 
+#[test]
+fn test_vertical_tabs_panel_closed_when_disabled_even_if_persisted_open() {
+    // Regression for #9505: when `vertical_tabs_panel_open=true` is persisted
+    // and the user then disables vertical tabs, restoring the workspace must
+    // not honor the stale snapshot — otherwise a dismiss underlay paints over
+    // the window and silently swallows every click.
+    let _vertical_tabs_guard = FeatureFlag::VerticalTabs.override_enabled(true);
+    App::test((), |mut app| async move {
+        initialize_app(&mut app);
+
+        // Snapshot the workspace with the panel open while vertical tabs are enabled.
+        app.update(|ctx| {
+            TabSettings::handle(ctx).update(ctx, |settings, ctx| {
+                report_if_error!(settings.use_vertical_tabs.set_value(true, ctx));
+            });
+        });
+        let workspace = mock_workspace(&mut app);
+        let open_snapshot = workspace.update(&mut app, |workspace, ctx| {
+            workspace.vertical_tabs_panel_open = true;
+            workspace.snapshot(ctx.window_id(), false, ctx)
+        });
+
+        // Disable vertical tabs, then restore. The panel must stay closed.
+        app.update(|ctx| {
+            TabSettings::handle(ctx).update(ctx, |settings, ctx| {
+                report_if_error!(settings.use_vertical_tabs.set_value(false, ctx));
+            });
+        });
+        let restored = restored_workspace(&mut app, open_snapshot);
+        restored.read(&app, |workspace, _| {
+            assert!(!workspace.vertical_tabs_panel_open);
+        });
+    });
+}
+
 #[test]
 fn test_vertical_tabs_panel_defaults_open_for_new_window_when_vertical_tabs_enabled() {
     let _vertical_tabs_guard = FeatureFlag::VerticalTabs.override_enabled(true);