If you disable a Define PropertySet action, the variable still gets created.
This is as designed… it’s a limitation of how propertysets (and filesets, and any other objects owned by the project, like xmldocs, ftp connections etc) are stored. We did look at this a while back to see if we could remove the object if the action was disabled, however then it removes the references to the propertyset on other actions. I have some ideas to look at for this for a future version so this may change in FB8 (no guaratees).