I have been working with After Effects CS6 on a project. Everything was fine. I started a new project and suddenly the dropdown menu arrows aren't responding in the effects panel, effect controls panel. When I open the prior project, the problem persists there as well. I reinstalled the software and updated to 11.0.3 and still have the same problem. I am running Sierra on a Mac.
Anyone have a possible solution to this problem?
Try trashing preferences. Does that work for you?
Keep in mind that CS6 was written years before Sierra came out, so you may experience unexpected behavior going forward if you continue to update your OS. At some point, you may want to lock that down or update to CC.
If you still need help, do let us know.