doesn't work on Mac with Qt-4.3

[Bennett Helm]

I just noticed that <opt><shift><tab> (which in mac.bind is specified  
as buffer-previous) does not work with current svn compiled with  
Qt-4.3 on Mac. Investigating with -dbg key reveals that the <tab> key  
is not recognized as being pressed *except* when <opt> (and only  
<opt>) is already pressed. That is, <tab> alone isn't recognized, nor  
is <shift><tab> nor is <opt><shift><tab>.

Any idea what's going on?
Bennett