saving/restoring the panel configuration is not done well. if panel is being killed, and then the session is restarted (no session saving), next time there is just empty panel - all it's config is gone: the panels.xml file is being freshly overwritten. Similar thing happens if one of the panel items got killed (e.g. killall xfce-weather, or SEGV or whatever). Next time it would not start at all - it is being removed from panels.xml. Seems someone always overwrites this file at eo-session?
Unfortunately I can't reproduce this. With revision 23341 I have commited something to SVN that might help to fix this problem. It will be available in the next release candidate. Thanks for the report. BTW, the plugin behavior is intentional. If a plugin crashes there is a problem that should be fixed before starting it again. If you kill a plugin... why kill a plugin if you don't want it to go away?
Could you try again with Xfce 4.4 RC2?
I tried several times to kill my X session [Ctrl-Alt-BackSpace] and no plugins were lost. I had say, this is a go for FIX. Mike
This really should be fixed, as Mike has confirmed. Please reopen if it still happens in the latest Xfce release.