I have an interesting issue with the task manager button graphic for open windows.
When I have less than 4 open windows I get corrupted task manager button graphics for the inactive windows.

The task manager button graphic show two sets of two white windows that are cascaded. The front one has the K with a gear like the K in the app launcher button.

If I open 4 or more this glitch goes away.
This is on an intel Q35 video card running debian sid/experimental.
Using UXA accel and KMS and intel driver 2.7.99 (happened with 2.7.X too)

I don't have a crash but just the glitch.

Anyone else have this? Should submit a KDE bug?

Well either a new build of 2.6.30-rc4 or fixing my MTRR fixed this.