User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9b5) Gecko/2008032619 Firefox/3.0b5 Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9b5) Gecko/2008032619 Firefox/3.0b5 The "Clear Private Data" popup window has a lozenge in the upper-right hand corner as if there are hidden buttons or toolbars or other widgets. It should not, since pushing it does nothing and there is nothing else that can be made to appear in this dialog. Reproducible: Always Steps to Reproduce: 1. Go to Tools > Clear Private Data… Actual Results: The displayed dialog has the lozenge present. Expected Results: The displayed dialog should not have the lozenge present. I have attached a screen shot.
Confirmed in latest trunk (Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; fr; rv:1.9pre) Gecko/2008050804 Minefield/3.0pre).
The downloads window has the same problem, and I wouldn't be surprised if there were a few other places where the same thing happens.
Fixed by bug 269410.