Since bug 642163 checkin, the composition window is badly broken when both the contacts pane and the attachment pane is present. Backing off to Mozilla/5.0 (Windows NT 5.1; rv:5.0a2) Gecko/20110502 Thunderbird/3.3a4pre the problem goes away. This is with Winxp pro running on a laptop at 1024x768 res

This is probably going to be WFM After upgrading to current trunk, I'm now not able to reproduce. The only unexplained oddity, is that the original screenshot had a width of 1022 px Now after the re-update screenshots result is a normal 1024 width and the symptoms are not seen. Go figure. I'll watch it for a while, then mark wfm.

It still may be worth investigating, even if it just occurs under rare and specific circumstances. Apparently the listbox comes with its own overflow handling, thus you want scrollbar on an overflow-y but not an overflow-x. Maybe adding something like "overflow-x: none;" would prevent this from happening if some numerical issue results in the box being a pixel short?

Unable to duplicate this condition. While the symptoms most likely resulted from a non-standard display width of 1022 px, I have not been able to recreate that condition. So without STR marking worksforme