same issue for me, the only stable solution that I've found to get working panels through different login was to remove compiz.
So, I run sudo aptitude remove compiz compiz-core
After that, panel works fine.
Furthermore, if you want to really use compiz on this hardware you can reinstall it and from now on everything it's ok.
PS: I've not run a dpkg-reconfigure on compiz packages, possibly it should be enough.
same issue for me, the only stable solution that I've found to get working panels through different login was to remove compiz.
So, I run
sudo aptitude remove compiz compiz-core
After that, panel works fine.
Furthermore, if you want to really use compiz on this hardware you can reinstall it and from now on everything it's ok.
PS: I've not run a dpkg-reconfigure on compiz packages, possibly it should be enough.