src/java.desktop/share/classes/javax/swing/plaf/basic/BasicInternalFrameUI.java

@@ -117,10 +117,11 @@
     /**
      * Installs the UI.
      * @param c the component
      */
     public void installUI(JComponent c)   {
+        super.installUI(c);
 
         frame = (JInternalFrame)c;
 
         installDefaults();
         installListeners();