public MenuData cloneData() {
		MenuData newData = new MenuData(menuPath, icon, menuGroup, mnemonic, menuSubGroup);
		newData.parentMenuGroup = parentMenuGroup;
		return newData;
	}
The subgroup string.  This string is used to sort items within a 
{@link #getMenuGroup() toolbar group}.  This value is not required.  If not specified, 
then the value will effectively place this item at the end of its specified group.
Ghidra/Framework/Docking/src/main/java/docking/action/MenuData.java