private void addOverlayIcon(IconValue overlayIconValue) {
		if (overlayIconValues == null) {
			overlayIconValues = new ArrayList<>();
		}
		overlayIconValues.add(overlayIconValue);
	}
Parses the given string as one or more icon modifiers
@param iconModifierString the string to parse as modifiers
@return an IconModifier as specified by the given string
@throws ParseException if the iconModifierString in not properly formatted icon modifier
Ghidra/Framework/Gui/src/main/java/generic/theme/IconModifier.java