Wow, that was tricky! Anyway, I'm back on the PC now. It seems that when you hold shift, it seems to accept that as a key press, as opposed to a modifier of some kind. (If that's the correct word)

On my 770's screen I get little boxes, well - more like [ ] but rotated through 90degrees, so they're at the top and bottom of where a character would be.

Sorry I can't be more help.