Clicking the hud disabled

On my normal account, if I left-click on any button/ability and it would work. I used to be able to click Q and then cast it by clicking again.

But now on my new account/smurf. I can't click on abilities anymore. It just does nothing.

This is extremely annoying as I'm often drinking/playing with my pets during times of little action where I'm able to use one hand safely to just farm or something.

can someone tell me how to change this? I've carved through the entire options menu I see nothing.