public void setToolBarSubGroup(String newSubGroup) {
		if (SystemUtilities.isEqual(toolBarSubGroup, newSubGroup)) {
			return;
		}
		ToolBarData oldData = new ToolBarData(icon, toolBarGroup, toolBarSubGroup);
		toolBarSubGroup = (newSubGroup == null) ? NO_SUBGROUP : newSubGroup;
		firePropertyChanged(oldData);
	}
Returns the subgroup string.  This string is used to sort items within a 
{@link #getToolBarGroup() 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.
@return the subgroup
Ghidra/Framework/Docking/src/main/java/docking/action/ToolBarData.java