diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index 24ced0c171..9e056fe774 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -5420,14 +5420,20 @@ corner_rect (cairo_rectangle_int_t *rect,
 }
 
 static void
-subtract_corners_from_region (cairo_region_t        *region,
-                              cairo_rectangle_int_t *extents,
-                              GtkStyleContext       *context,
-                              GtkWindow             *window)
+subtract_decoration_corners_from_region (cairo_region_t        *region,
+                                         cairo_rectangle_int_t *extents,
+                                         GtkStyleContext       *context,
+                                         GtkWindow             *window)
 {
   GtkWindowPrivate *priv = gtk_window_get_instance_private (window);
   cairo_rectangle_int_t rect;
 
+  if (!priv->client_decorated ||
+      !priv->decorated ||
+      priv->fullscreen ||
+      priv->maximized)
+    return;
+
   gtk_style_context_save_to_node (context, priv->decoration_node);
 
   corner_rect (&rect, _gtk_style_context_peek_property (context, GTK_CSS_PROPERTY_BORDER_TOP_LEFT_RADIUS));
@@ -5485,7 +5491,7 @@ update_opaque_region (GtkWindow           *window,
 
       opaque_region = cairo_region_create_rectangle (&rect);
 
-      subtract_corners_from_region (opaque_region, &rect, context, window);
+      subtract_decoration_corners_from_region (opaque_region, &rect, context, window);
     }
   else
     {