Tabbing works stand alone, and in editor.
Webplayer still doesn't work, even if I use Up/Down arrows for the events. It's like NGUI is eating the event or something. This is only the case for UIInputs.
#Edit: In fact I'm fairly certain NGUI is eating the event somehow, because when I use the up/down arrow, instead of listening to my logic, the i-beam moves to the beginning or end of the typed input. How can override this behavior, or add onto it?
Yet... why would it only seem to override in the web player? Bwah...
Although somehow you have it working, but only if I use the UIKeyControl... then somehow tab works.
#Edit2: I ended up using Left+Control as Shift+Tab, and Right+Control as Tab.