Oh I see what you mean now. Hmm I think if you turn off the hotbar help in the settings, you can remove the box. However the names for your actions won't show either when you are preparing to select them, so if you know what you are using then thats the only way.

I have it like this just the icons which is nicer, though I'm not sure of the exact place in the settings but if you cannot find it I'll try to get online and check for you and post it here.