The "Unread Threads" link used to cover the "Advanced Search" link but I never mention it because I never used the link. For some reason now it is covering the breadcrumb links that I use often.
See attachment: sitepoint.issue.png
It seems to be because the .navtabs ul is positioned absolutely. There's no real reason to use position: absolute; in this case. It should be removed.
On a similar note, I also notice that the topic links have gone bold all the time instead of bold if unread and normal if read.