Originally Posted by Mr_PiCaLo
I believe the short answer is that X doesn't support 32 bit color, and as such it doesn't support alpha channels in basic operations. That's why things like window shadows arn't anything more than hacks right now.
I think that the freedesktop.org server is changing this... but i'm not sure
Thats funny because the Matrox line of cards do 32bit in X, both Nvidia and ATI only support 24 bit.