Nobody can tell you anything without proper system info or other technical details liek version of AE. On the otehr hand I believe there is a known bug in recent versions of AE with exactly that behavior...
Thanks for your response!
I am using the latest version CC5.5.
It is just so weird since I have been using vertex tool so smoothly before. (So I dont reckon its my computer's problem)
But maybe I opened some old version project files which might clash with the newest version?
Ohh My bad. Sorry for wasting you time on this dumb questions.
Thanks for the help!
not at all please mark the response so this thread can be tagged as answered. other users can find this information quickly and users like me get another little nifty Equalizer bar.