There is nothing special to do with the menu regarding the tags screen. As I’ve said a few times everything behaves perfectly fine with the event calendar plugin DISABLED. No other configuration changes are made besides that.
In short go here http://8e3.070.myftpupload.com/category/body-of-knowledge/ click on anything in the tag cloud on the sidebar and the top menu disappears. It behaves this way only with the event calendar plugin enabled. Clicking on anything in the categories section works fine.