Resize error - persistent grey bar above Zotero

I've got a bug with resizing the Zotero pane. Making it smaller leaves a grey background up to where it used to be. Minimising it leaves this grey bar visible.

I can get rid of it by resizing the Zotero pane up to the level of the grey background (or higher) and then minimising, but this means I can't have a small Zotero pane, and the grey background just gets bigger and bigger each time I try!

Restarting FF resets back to normal, but it comes back - though not straight away. I haven't isolated what initiates the problem (restarting takes a while), but I think it's every time I add a new item.

I'm on FF 3.5.2, Zotero 2.0b6.5, Win XP-SP3 (5.1.2600).
I do (of course) have lots of other plugins going.
This discussion has been closed.