Using 2000092110. On the sidebar, hit the "Tabs>" button, then choose "customize sidebar". The box that comes up will be sized too small for the items in the box, cutting the Cancel button in half vertically, as well as the up/down button.
confirmed with 092208 mozilla trunk builds.
nominating beta3. This looks bad and shud b easy to fix.
this got fixed a while ago. marking FIXED
verified with trunk build 20001120 on linux.