I have the same problem!
Are they installed into the Application though? That is the main thing.
Could you clarify what you mean by "installed into the application"? I've encountered many instances where a valid CC extension can be installed in AEM, shows checked, the "load extension panels" preference is checked in Photoshop - and yet the panel does not show up under Window/Extensions. Note that I rarely (if ever) encounter issues with CC2014. Reinstalling CC (even if you already have the latest version) seems to fix it, but am looking for a simpler solution to make sure the panel can be consistently installed in CC without issue.