I'm posting here as the anomaly I've found involves both my stable 32 bit system
and my test5 64 bit system, which makes me feel that neither "Software" nor "Testing" would be the right section.
Anyway, lately I get this dialogue on log in to either test5 or my fully updated 32 bit KDE system:

It looks more or less like a tooltip and drops down from the panel at the top of my screen. There is nothing to indicate what or who it is that needs the panel, or why neither of my existing panels will do. I usually just click "OK" and everything is well.
But why do I get the dialogue window or tooltip?
I've tried removing the icons on my panel one by one to see if that would make a difference, but not surprisingly it doesn't. I suppose that If whatever it is that needs a panel already resided on a panel it wouldn't complain.
I'm not sure, but it is possible that this started on my 32 bit install after I had upgraded KDE to 4.8.3. But if so, why don't I get the window on my fully updated test4 install, which is also upgraded to 4.8.3?
All my systems have the same icons on the panels.
This isn't really a problem, but it is a bit of a brain-teaser.