Suggestion: When searching for "properties", include "Install Parameters" in the filtered results list, as that's where you can add/edit/delete properties. I took quite a while trying to find where to delete properties I didn't need, or wanted to edit after naming wrongly or added with incorrect default value.
Alternatively, could you allow the user to edit/delete properties from within the Properties popup dialog? You can add new user-defined properties here and it would be logical to allow r-click options to edit/delete them from here too.