Went to boot my machine today, after logging in and typing startxfce4, my cursor showed as a large block made of dots, and the screen was all black with evenly spaced dotted lines of red green and blue.
I just downgraded. It didn't bother me as XFCE is working just fine as-is.
If anyone knows of a quick solution thats fine otherwise don't waste your time. Wondering if anyone else is experiencing the same problem too.
Lenovo T400 ATI 3000HD Graphics
Sounds more like a driver problem to me. Have you updated catalyst at the same time as the other packages?
I'm using xfce (all packages up-to-date) with a Radeon HD2400 (with the free driver, radeon) and everything works well.
The driver is up to date, using the proprietary driver which may be the problem.