How to disable Big Picture in Desktop Mode?

My only real complaint with my Deck has been the frustration of trying to use the On-Screen keyboard in desktop mode. Often when I open it using the Steam Button + X hotkey, it launches Big Picture Mode instead of giving me a keyboard.

Is there a way to disable BPM from opening at all? I know on PC and Linux you can do so, but I can't find the option on my deck.