How do you assign a Hotkey to a Button?

I see there's a Hotkey field under Control in the Button Properties, but it shows "None" and there are no controls on it to assign a hotkey. I'd like to bind the selection of a specific camera on my keyboard, I understand I have to make a button, add an Action which calls the exact string of the specific camera... but how do I assign it to my keyboard?

I just found out I bugged the interface of the editor with a saved layout!! It kept on giving me some unassigned object error while I was trying to do a new label, then I noticed the ticker was disabled and with no little arrow to expand the menu... So I restarted the editor with a clean layout and both the arrows for the ticker and the hotkey came back!!

problem... solved-ish?