This is something that crops up in Chrome and IE, but not Firefox, which unfortunately MIGHT mean it's an issue with the browsers and not with the plugin. That said, I added onto your example capx to show you the problem:
All I did was add a single event at the bottom, "on B pressed", that increments an arbitrary variable. Because of this event, if you try to read in the scan code, unicode char, and unicode code for the B key, you'll only get the scan code; the other two won't work. It works for every other key, but if there are events using the key, it won't.
Think you can take a look at it for me?