This app works just like advertised. Very well done.
Update:
Now whenever I open the app I get a big square the covers about 1/3 of the screen beginning in the top left corner. It appears to be some kind of message box, but it contains nothing and I can't get it to go away. Also with this box on the screen I can't access the calibration or any of the other buttons at the bottom of the screen. Perhaps the developers will read this and either tell me how to get rid of this box, or fix the app so it doesn't appear.
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