modules/javafx.graphics/src/main/java/com/sun/glass/ui/gtk/GtkWindow.java

*** 226,231 ****
--- 226,236 ----
  
      @Override
      protected void _releaseInput(long ptr) {
          throw new UnsupportedOperationException("Not supported yet.");
      }
+ 
+     @Override
+     public long getRawHandle() {
+         return getNativeWindow();
+     }
  }