I recently switched to using xfce on my FreeBSD desktop. Window Maker is nice but it was starting to feel a bit dated. Thus far I like xfce, but I had one problem with Terminal. Whenever I tried to resize it or switch desktops to one with Terminal open in it I could see it painstakingly render the window. Xterm and aterm didn't exhibit this behaviour, my 3d was accelerated, and other screen drawing didn't show problems either (do note I am using NVIDIA's binary driver for my GeForce 8800, the nv driver from X.org is unusable at this point).
Someone pointed me at the environment variable XLIB_SKIP_ARGB_VISUALS=1. Once added to .zshenv, properly exported on my shell and an X restart later I find Terminal to zoom along as expected. It turns out that the NVIDIA driver doesn't properly accelerate alpha channels.