Hey all
I want to report this, but don't know how to use the bug tracking system because I'm not sure which package is the problem. I think it's lxpanel.
I've been upgrading all the machines in my vicinity to jessie, simply using an aptitude dist-upgrade from wheezy, and it's gone fine. Recently I wanted a fresh install on a machine and I had a wheezy net-inst cd around, so I installed that and then did the aptitude dist-upgrade after changing the sources. Unlike every other time I have done this, I never logged into LXDE first.
When jessie was installed, I logged in, and the panel was missing. I reinstalled Wheezy and then logged in and then redid the upgrade, and the panel was there.
So I'm guessing whatever part of LXDE makes the default panel settings is missing from the package currently in Jessie, and that I got it worked out by letting the package in wheezy write the configuration.
Anyway, the problem's solved for me, but I wanted to pass it on.