The issue should be fixed in maverick now with that change:
libwnck (2.30.0-2) unstable; urgency=low
* Switch to 3.0 (quilt) format.
* 01_vertical_panel.patch: patch from Carey Underwood and Leniviy to
fix lockups when the window list applet is on a vertical panel.
Closes: #524117.
If the fix is confirmed to work it will be backported to lucid later
The issue should be fixed in maverick now with that change:
libwnck (2.30.0-2) unstable; urgency=low
* Switch to 3.0 (quilt) format. panel.patch: patch from Carey Underwood and Leniviy to
* 01_vertical_
fix lockups when the window list applet is on a vertical panel.
Closes: #524117.
If the fix is confirmed to work it will be backported to lucid later