Comment 23 for bug 518873

@itsjustarumour
There is one possibility I started to wonder about last night. This is admittedly a shot in the dark, but one of the changes in the gnome-panel Change Log for Ubuntu Lucid is some changes to prevent crashes due to Xrandr. I was just recently working on another report that ended up being due to Xinerama conflicting with Xrandr. It is difficult to say if this could possibly be happening on your system too, especially since Xinerama is used for dual displays, but could you attach your xorg.conf file to this report? That will show whether Xinerama is enabled on your system or not so we can see if that is possibly related in any way. Depending on what your xorg.conf file says, I have a few ideas on how we can approach this bug. Thanks in advance!