Why did my keyboard shift so I can't see half of it

[Android Central Question]

my keyboard shifted was something I pressed so that half of it is missing in the top left corner and there's all this open space and I don't know what to do

 

[deltaTgm]

Are you talking about the function button on left or right side? I've seen it on default Samsung phone. Annoying. I replace it with BlackBerry keyboard.