Mac keybinding for cycling between buffers

[Bennett Helm]

Current keybindings on the Mac for the new buffer-next and 
buffer-previous functions to cycle between buffers don't work: it 
appears the Mac is intercepting <cmd>` and <cmd>~ and using them to 
switch between windows (including between dialogs and the main window). 
So we'll need other keybindings.

Switching between buffers in the single LyX window seems most like 
switching between tabs in an internet browser. There are three models 
here:

1. Safari uses <cmd><shift>left/right-arrow for this; this conflicts 
with the Mac standard keybinding for select to beginning/end of line.

2. Camino uses <cmd><opt>left/right-arrow; this conflicts with the 
current mac.bind keybinding for increase/decrease environment depth.

3. Firefox uses both <ctrl><tab>, which can't be accessed with the LyX 
keybindings, though <opt><tab> can and is otherwise unassigned.

So I propose that <opt><tab> (M-Tab) and <opt><shift><tab> (M-BackTab) 
be used for switching between buffers in mac.bind. This would parallel 
the use of <cmd><tab>, which is the Mac standard keybinding to cycle 
between applications. (Another option would be to go with cua.bind's 
<cmd><page-up/down>, which is also currently unassigned.)

Any better ideas?
Bennett