AppletStageExtension's useDefaultClose: false is not working

Steps to reproduce:
Goto - http://javafx.com/samples/CustomSplashScreen/
Drag the applet out. - Please find the attached scree shot.

In his code.
      AppletStageExtension {
            onDragStarted: function() {
                vis = true;

            }
            onAppletRestored: function() {
                vis = false;
            }
            useDefaultClose: false
        }

Still close button is shown.