fix(linux): clear stale shadow input region when restoring title bar

src/platform/linux/window_linux.cpp

@@ -40,6 +40,7 @@ static const char* kMouseInputPolicyKey = "NativeAPIMouseInputPolicy";
 struct MouseInputPolicy {
   bool ignored = false;
   bool forward = false;
+  bool shadow_rectangle = false;
   guint source = 0;
   GtkWidget* widget = nullptr;  // The owner, or nullptr for a bare GdkWindow.
   GdkWindow* surface = nullptr;
@@ -239,6 +240,17 @@ static void ApplyMouseInputPolicy(GtkWidget* widget, GdkWindow* surface,
   else gdk_window_input_shape_combine_region(surface, region, 0, 0);
   if (empty) cairo_region_destroy(empty);
 }
+
+static void ClearShadowInput(GtkWidget* widget) {
+  auto* surface = gtk_widget_get_window(widget);
+  auto* policy = GetMouseInputPolicy(widget, surface, false);
+  // Ownership survives surface recreation; explicit input/visual shapes stay intact.
+  if (!policy || !policy->shadow_rectangle) return;
+  cairo_region_destroy(policy->region);
+  policy->region = nullptr;
+  policy->shadow_rectangle = false;
+  ApplyMouseInputPolicy(widget, surface, *policy);
+}
 static const char* kTitleBarStyleKey = "NativeAPITitleBarStyle";
 static const char* kFocusableKey = "NativeAPIFocusable";
 static const char* kNonActivatingKey = "NativeAPINonActivating";
@@ -2678,12 +2690,14 @@ static cairo_region_t* RasterizeShape(GtkWidget* widget, GdkWindow* window,
   return region;
 }
 
-static void ApplyInputRegion(GtkWidget* widget, GdkWindow* window, cairo_region_t* region) {
+static void ApplyInputRegion(GtkWidget* widget, GdkWindow* window, cairo_region_t* region,
+                             bool shadow_rectangle = false) {
   // GTK intersects its CSD input region with the explicit widget region. Register
   // ours with GTK as well as GDK so a later allocation cannot overwrite it.
   auto* policy = GetMouseInputPolicy(widget, window, true);
   if (policy->region) cairo_region_destroy(policy->region);
   policy->region = region ? cairo_region_copy(region) : nullptr;
+  policy->shadow_rectangle = shadow_rectangle;
   ApplyMouseInputPolicy(widget, window, *policy);
   g_object_set_data(G_OBJECT(window), kInputShapeKey, region ? GINT_TO_POINTER(1) : nullptr);
   gdk_window_invalidate_rect(window, nullptr, TRUE);
@@ -2703,7 +2717,7 @@ static void RefreshShadowInput(GtkWidget* widget) {
     rectangle.AddPoint({double(width), double(height)}); rectangle.AddPoint({0, double(height)});
   }
   auto* region = RasterizeShape(widget, window, explicit_polygon ? shadow->polygon : rectangle);
-  ApplyInputRegion(widget, window, region);
+  ApplyInputRegion(widget, window, region, !explicit_polygon);
   cairo_region_destroy(region);
   g_object_set_data(G_OBJECT(window), kInputShapeKey, explicit_polygon ? GINT_TO_POINTER(1) : nullptr);
 }

src/platform/linux/window_shadow_linux.h

@@ -7,6 +7,7 @@
 
 namespace nativeapi {
 static void RefreshShadowInput(GtkWidget* widget);
+static void ClearShadowInput(GtkWidget* widget);
 }
 
 namespace nativeapi::linux_shadow {
@@ -271,6 +272,7 @@ inline void Remove(GtkWidget* widget) {
   const int width = child ? gtk_widget_get_allocated_width(child) : 0;
   const int height = child ? gtk_widget_get_allocated_height(child) : 0;
   g_signal_handlers_disconnect_by_data(widget, state);
+  ClearShadowInput(widget);
   gtk_style_context_remove_class(gtk_widget_get_style_context(widget), kGutterStyleClass);
   if (state->overlay && child == state->overlay) {
     auto* content = gtk_bin_get_child(GTK_BIN(state->overlay));