Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1186932
Description of problem:
When you create or edit a config group, the tooltip for adding a class is "Click to add <class name>". After you click that, you can then remove it, and our tooltip for that is "Click to undo adding this class".

We could make those more concise if we simply said "Add this class" and "Remove this class". By nature of being a tooltip on a clickable element, I think it's implied that if they click it, the action the tooltip says will happen. 'Remove' is the more expected opposite to 'add' than 'undo adding'.

Version-Release number of selected component (if applicable):
6.0.6