modules/javafx.graphics/src/main/native-glass/gtk/GlassWindow.cpp

@@ -80,12 +80,14 @@
 JNIEXPORT jlong JNICALL Java_com_sun_glass_ui_gtk_GtkWindow__1createWindow
   (JNIEnv * env, jobject obj, jlong owner, jlong screen, jint mask)
 {
     (void)env;
 
+    WindowContext* parent = JLONG_TO_WINDOW_CTX(owner);
+
     WindowContext* ctx = new WindowContextTop(obj,
-            (WindowContext*)JLONG_TO_PTR(owner),
+            parent,
             screen,
             glass_mask_to_window_frame_type(mask),
             glass_mask_to_window_type(mask),
             glass_mask_to_wm_function(mask)
             );

@@ -106,13 +108,15 @@
     GdkWindow *parent_window = NULL;
     GtkWidget *parent_widget = NULL;
     WindowContextPlug *parent_ctx = NULL;
     WindowContext *ctx = NULL;
 
+    WindowContext* parent = JLONG_TO_WINDOW_CTX(owner);
+
     parent_window = gdk_x11_window_lookup_for_display(
                         gdk_display_get_default(),
-                        (GdkNativeWindow)PTR_TO_JLONG(owner));
+                        GDK_WINDOW_XID(ctx->get_gdk_window()));
 
     if (parent_window != NULL) {
         parent_ctx = (WindowContextPlug *)g_object_get_data(G_OBJECT(parent_window), GDK_WINDOW_DATA_CONTEXT);
         // HACK: do not use get_gtk_window()
         // the method is intended to return GtkWindow that can be used for FileChooser