May I know how you came to such conclusion? I see no difference when comparing two simultaneously running instances of OMP in htop. I even compared with an ancient version from before OMP entered repositories, but I still don't know what you mean.
I assume that you're speaking of buttons which actually do something (otherwise I don't think it's a problem with OMP). I will disable key repeating for some shortcuts.
Hmmm... I don't remember listing any shortcuts for that. If you press Shift+Enter, you should get a keyboard-friendly version of that menu.