Recently, without a warning, my blog site stopped being properly displayed, when drilling down on the circumstances that prevented it from properly displaying at least, so far, I have found that when it is displayed with Firefox browsers the left navigation bar 'disappears'. If displayed with Internet Explorer it is properly displayed.
I had not realized about this fact, but when Eduardo Legatti asked me what happened with the left navigation bar it was when I entered as a regular non authenticated user, I saw something happened with my Blog Archive and my Topics menus, those were gone. Eduardo told me he uses also Firefox.
In my personal opinion my default choice is Firefox, just like 24% of the blog users, not Internet Explorer, unless due to VPN restrictions or bank access requirement. I have tried to change my layout, and unsuccessfully it behaves the same. So the workaround in the mean time is to click on the item menu or use Internet Explorer :(
Some people have reported differences between firefox and internet explorer [Resolving Browser Display Discrepancies Between IE and Firefox].
... After a couple of hours after publishing this post the left navigation bar is back again, it looks like there was some issue wiht the cache. I have removed the cache from firefox, but I am not sure this was the actual solution.