Please describe the problem:
I have a vertical panel in the upper right corner of my screen that contains the windowlist applet. When the number of open windows reaches the threshold where the applet starts displaying them in two columns, strange things start to happen:
most of the time when I switch between workspaces, the windowlist alternates between two-column layout and one-column layout which results in a list/panel that is double its normal size. This alternation also sometimes happens when just clicking on the desktop. Also, when trying to click on one of the apps in the list, sometimes the whole list starts to flicker between double/normal size.

Since this is probably a little hard to understand, I made a video. Just watch the panel in the upper right screen corner (ok, the quality sucks, but I think it's enough to recognize the problem). The URL is: http://one.eu.ro/tmp/gnome-windowlist-bug.avi

Steps to reproduce:
Look at the video - you can also hear when I click the mouse (always the left button)

Actual results:
see above

Expected results:
The windowlist should not change its size

Does this happen every time?
As soon as the two-column layout is triggered, yes

Other information: