Buffer on X vs. Classic

[cowhead]

I think this has already been discussed, but at the time I didn't quite
follow or pay attention.  Anyway,  I have this situation:

1.  a player is playing a quicktime movie (actually a GIF) with looping
2.  I move the player around while it is playing (using move relative)

In Mac classic, with the alwaysBuffer of the stack and player set to
true, the movement looks nice and smooth (although I think the player
pauses briefly during the move).

In contrast, with mac OSX, you must set the alwaysBuffer of the player
to false, or it disappears, at least briefly, during the move, giving a
choppy, blinky appearance.  With alwaysBuffer() set to false, the move
looks good as it does on classic. BUT:

3.  with always buffer set to false, a playing or paused player cannot
appear behind a field, even if the layer of the field is way over that
of the player.  I think this is true on both platforms.

So, why does the "alwaysBuffer" of a player work oppositely under X and
classic?  Bug?

thanks,
mark in Japan
(ps.  all results used latest test versions of Rev.)