private int getIconFocusWidth( JComponent c ) {
		AbstractButton b = (AbstractButton) c;
		Icon icon = b.getIcon();
		if( icon == null )
			icon = getDefaultIcon();

		return (icon instanceof FlatCheckBoxIcon)
			? Math.round( UIScale.scale( ((FlatCheckBoxIcon)icon).getFocusWidth() ) )
			: 0;
	}
Returns the default background color of the component.
If the component is used as cell renderer (e.g. in JTable),
then the background color of the renderer container is returned.
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatRadioButtonUI.java