The existent menus "projnav" and "backnav" depend on a modifed trac.css header.cs and wiki.cs.
Those should be provided from within the plugin.
See this thread for a possible solution:
http://groups.google.com/group/trac-users/browse_frm/thread/07b798df7e373dda?tvc=1
Milestone rework deleted
(In [53]) closes #36, corrections, inclusion of the patch to deactivate modifications when plugin is deactivated.
(In [52]) re #36, css can be overridded within plugin, no longer needed to be under version control
(In [51]) closes #36, css modifications provided from within the plugin
mechnism for *.cs templates implemented within #41