I just got my pro1x and was having several problems with the camera button, the biggest one being that it was taking photos in my pocket from the lock screen and leaving phone in the camera app. Additionally the snapdragon camera app showed portrait image if the keyboard was open.
Anyway to resolve, I installed opencamera and disabled snapdragon camera app. I used keymapper to set the camera button to open the camera app as well as shutter.
This works much better. From lock screen, it still wakes device which I havent figured out how to disable, but at least it doesnt launch camer