I asked a similar question some time ago : http://www.mapleprimes.com/questions/123925-Shortcut-Key-AltShiftF6.
I'm still on Maple 13, and I still have not found a way to switch between tabs/windows using the keyboard.I am in the one Maple session (ie I haven't started a new one).
I tried all suggested combinations, including all combinations of Ctrl, Alt and Shift with F6. I also tried Ctrl-Tab. All to no avail.
Any help appreciated.