Tested in OSX only. Safari 3 & 4. See: http://dl.getdropbox.com/u/28951/menu.png . The top menu (in dutch im afraid) is misaligned. A CSS problem? This is with build: r41176 Problem started with build r41071 and beyond. Build r41018 worked fine.
Cionfirmed as a regression.
This was fixed between r41521 and r41545, possibly by r41538: http://trac.webkit.org/changeset/41538