Edit box on the "flag" link for a post goes outside the "window" borders.
All similar flag dialogs in which there's an edit box are affected.
Reproducible on both main site and meta, using both Firefox 3.6 and Chromium 9.0 on Ubuntu 10.10. Not reproducible on Chrome 10/Firefox 4.0b12/IE9 on Windows 7.
Possibly related: this issue from a week or so ago (the same pattern of OSes being affected).