Description of problem:
the "+Add" link next to the dropdown for "Add Products and Repositories" only works when the dropdown item selected is a top level provider. It should either be disabled when choosing a repo, or it should be fixed to allow selection of repos.

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


How reproducible:


Steps to Reproduce:
1. Sync RH and EPEL content
2. Content management > providers > Package Filters > +New Filter
3. Create new filter, "fibble".
4. fibble > Products and Repositories
5. Attempt to choose a sublevel item from the products and repos dropdown (like RH or EPEL repos); click +Add.
6. Attempt to choose a toplevel item from the dropdown (like the respective RH and EPEL products themselves); click +Add.
Actual results:

User cannot select repos themselves.

Expected results:

Either user should be able to select repos, 
or 
+Add should be disabled for those menu items. 

Additional info:

 Actually, since selecting a product automatically creates a secondary dropdown for its repos, I'm not sure why repos show up in the top box in the first place.