I tried to reproduce this without success using the following two builds (also on Win32) and the latest Noia2 theme Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.10) Gecko/20050716 Firefox/1.0.6 Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8) Gecko/20051103 Firefox/1.5 ID:2005110304 Noia 2.0 (eXtreme) 2.991 Perhaps it is an extension or userContent.css modification... try with a new profile to see if you can reproduce. Also, the Extension/Theme Manager manages the install, upgrade, update, uninstall, etc. for extensions and themes... it does not manage the interaction of extensions and themes beyond that.
Reporter - are you still experiencing this? If so, please try with a new profile. This is still WFM with Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20051121 Firefox/1.5 ID:2005112104 and Noia 2.0 (eXtreme) 2.991