Thank you so much for your feedback! :)
Concerning the white rectangle issue, we identified the problem and are testing a fix right now. In case we don't encounter any major issues with this, it will be fixed with the next update.
The problem with the "not responding"-dialogue can be worked around by starting the game in fullscreen. However, you have to make a task switch out and back into the game, so it can register your mouse clicks properly. This seems to be a bug reoccuring in a lot of unity engine versions and we just reported it again to the developers, hoping to get a fix for the LTS stream.