The crash occurs on session start. Trace logs can be found here: https://bugs.launchpad.net/ubuntu/+source/xfdesktop4/+bug/1282509 xfdesktop 4.11.3
Created attachment 5366 Fix segfault on session start
This makes the refresh into a no-op if workspaces is null. The icon refresh (which is the reason this is now getting called) doesn't rely on workspaces, so this may not be an appropriate fix. I would like to know *why* workspaces apparently haven't been set up when this is getting called.
On session startup gtk does send a style set before libwnck has initialized and sent its workspace created messages. Pushed to master in: http://git.xfce.org/xfce/xfdesktop/commit/?id=6583a1a632779e72ba6ecfa32a10f30980081876 Thanks for the patch!
Marking resolved