private URL getUrl(Icon icon) {
		if (icon instanceof UrlImageIcon urlIcon) {
			return urlIcon.getUrl();
		}
		else if (icon instanceof TranslateIcon translateIcon) {
			return getUrl(translateIcon.getBaseIcon());
		}
		else if (icon instanceof DerivedImageIcon derivedIcon) {
			return getUrl(derivedIcon.getSourceIcon());
		}
		else if (icon instanceof RotateIcon rotateIcon) {
			return getUrl(rotateIcon.getSourceIcon());
		}
		else if (icon instanceof GIcon) {
			return getUrl(((GIcon) icon).delegate);
		}
		// else if (icon instanceof MultiIcon) {
		return null;

	}
Returns the url used to load the icon delegate of this class.  If the delegate icon was not 
loaded from a url, then null will be returned.
@return the icon or null
Ghidra/Framework/Gui/src/main/java/generic/theme/GIcon.java