I see this too across different themes, so I would suspect it's a gtk thing.
** Changed in: Ubuntu Sourcepackagename: None => gtk+2.0 Status: Unconfirmed => Confirmed -- mouse-over on buttons doesn't work if mouse inside at button creation time https://launchpad.net/bugs/86030 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs