Yesterday was a big day for bug fixes. The biggies were Copy and Paste for ie6, and disappearing navigation in various browsers.
Disappearing navigation affected a lot of you, both in ie and some versions of firefox on windows. Yesterday, we spent a few hours restructuring the html for our navigation, and cleaning up our theme files. The problem seems to have vanished in our testing, but please let us know if you still see this issue.
For the techies out there, the copy and paste bug was caused by an odd combination of floating divs and the usage of a <base /> tag. Our fix was to replace <base /> with an uncommon, but still valid <base></base> tag.