Looks like it is roll over problem, that keyboard is not NKRO(I mean, 2KRO) and some 3-key combination may cause roll over error.
Hmm, you could be right. 3-key shortcuts for apps work though, such as Ctrl+Shift+Up, but clearly some error must be occurring while using this. At least I can get the basic feel for the HHKB setup

The arrow key modifier is more intuitive than expected using the pinky finger on the pseudo-Fn Shift key, but it's still a bit awkward, although the backspace position doesn't take much getting used to. Gaming-wise it would be simple enough to remap some other keys in-game if arrow keys were required.
It's a toss up for me whether it's more worthwhile (and cheaper) to just go with a compact Apple wireless keyboard, as the layout is perfect with the narrow arrow and function keys, and I'm used to typing on my MacBook. Yet there's something about the HHKB that I've always been attracted to - the aesthetic, the sound, the texture of the keys, those oh-so-sweet custom caps, and the community here...
Also: Happy New Year in advance to everyone
