Here's what we know about the issue with slowness when clicking to open a menu or when using a keyboard shortcut. (We're still digging, though, so it may turn out that some of this is incomplete or incorrect.)
Because of a change for After Effects CC (12.0) that shows the activated user in the menus, After Effects is checking a file on disk each time that menus are accessed. Because of the way that we implement keyboard shortcuts, this also means that the file is checked each time a keyboard shortcut is used.
On computers where disk access is slow (e.g., because the disk is slow, the bus is slow, or something else is reading from the disk at the same time), this simple check of a file can add a noticeable amount of time---maybe half a second or even a couple of seconds in some cases.
We are in the process of fixing this. It is my hope (but not a promise) that we'll be able to have a good fix in place for the next update, which we're targeting for September.
In the meantime, here's how you should be able to mitigate the problem:
Make sure that your software is installed on the fastest disk that you have, preferably an SSD. If you don't have an SSD, then at least make sure that your software (applications and OS) are not stored on the same drive from which you're reading footage or to which you're writing output files. And certainly don't run applications with high disk access (like WinZip or anti-virus software that intervenes at every disk access, just for a couple of examples) while you are working with After Effects. (BTW, this is all good advice for high performance even without this bug.)
If you make these changes and notice an improvement, let us know. Actually, let us know either way so that we can collect more information.
So, how did this get past us? I think that it's because we tend to test on computers that are set up as I describe above, including tending to use SSDs and having our disk access spread across multiple disks. That said, we do apologize for letting this get out and inconvenience you.
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Todd Kopriva, Adobe Systems Incorporated
After Effects quality engineering
After Effects team blog
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