This isn't specific to gedit. The exact same thing happens in similar dialogs with sound-recorder, mousepad, nautilus, xchat-gnome, so i'm thinking it's a gnome dialog bug.
-- Unnecessary tab positions in "unsaved changes" dialog https://launchpad.net/bugs/54948 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
