static Image getStateImage (Display display, boolean checked) {
	Image image = new Image (display, 16, 16);
	GC gc = new GC (image);
	gc.setBackground (display.getSystemColor (SWT.COLOR_YELLOW));
	gc.fillOval (0, 0, 16, 16);
	if (checked) {
		gc.setForeground (display.getSystemColor (SWT.COLOR_DARK_GREEN));
		gc.drawLine (0, 0, 16, 16);
		gc.drawLine (16, 0, 0, 16);
	}
	gc.dispose ();
	return image;
}