When you are using a phone in portrait, or when I am in 1/3 split screen (when it is displaying in a compact display such as hRwC), the chat is suppose to open covering the entire screen. But it will sometimes open too high on the screen (or be shifted too high off the screen). When this happens, it puts the new message and close buttons off the screen, and there will be a space below the chat box where you can see the world instead of the chat box. The only way to close the chat, on an iPad is to put The Blockheads into full screen or ½ (the regular display class view). If you are on a phone, you will just have to close the app. I forgot if rotating the phone works or not.
I am not 100% certain, but I am confident this happens when you tap the chat at the EXACT same time as a new message comes. This is somewhat hard to reproduce intentionally, because if you are less than a second off of exact, it doesn’t do it. But when it occurs unintentionally, it is annoying to have to change the screen size or close the app just to get rid of the chat box.
This bug has been around for a long time.
iPad Air 2
App Version 1.7.3