when I played with some friends and tap the chat button, I noticed that I hit my friend while the chat opened. I could also open and close doors if the chat button is over it. this problem happens on my iPod 4, my friends iPhone 5, two of my android tablets and android phone. so my guess is that this happens for most people since all these devices listed have the same issue.
I'm not sure if this has been reported but please fix this, in some cases it really frustrated me when I tried to type in chat and my friends hit me back when I almost finished typing what I wanted to say.
Fixed – Minecraft PE 0.9.5