Textbox crash

When you press the back button after you have the text box open in game, the game crashes

What I expected to happen was...:
The text box would minimize

What actually happened was...:
The game automatically crashes

Steps to Reproduce:
1. Get in the game
2. Click on the text button on the upper right.
3. Click on the box to begin writing text
4. Click the phone's back button. (Not the one on screen)