It's hard for me to explain but i try:
Normally you select the buttons (for example "Player sheets") with the mouse. But it happens really often, that after couple of minutes or even seconds sometimes, that the game itself select the buttons by his own without me. And it's moving around starting from the top and go straight to the buttom and so on. It's really disturbing. Restarting the game is the only way to stop it.
PS: It's only selecting not pushing the buttons.
Sorry but i can't explain it better.