protected void updateVisibility() {
		boolean visible = isWindowResizable();
		if( visible == topDragComp.isVisible() )
			return;

		topDragComp.setVisible( visible );
		bottomDragComp.setVisible( visible );
		leftDragComp.setVisible( visible );

		// The east component is not hidden, instead its bounds are set to 0,0,1,1 and
		// it is disabled. This is necessary so that DragBorderComponent.paintComponent() is invoked.
		rightDragComp.setEnabled( visible );
		if( visible ) {
			rightDragComp.setVisible( true ); // necessary because it is initially invisible
			doLayout();
		} else
			rightDragComp.setBounds( 0, 0, 1, 1 );
	}
Resizes frames, dialogs or internal frames.
<p>
Could also be used to implement resize support for any Swing component
by creating a new subclass.

@author Karl Tauber
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatWindowResizer.java