Duplicate Navbar in CF10 and CF11 Admin

I have completed the installation of both CF10 and CF11 on the same server (Win2008R2/IIS 7.5).  When I log into the administrator for either CF10 or CF11, I am presented with a duplicate navbar on the left (see below).  When I select an item on the navbar, it is properly displayed, and this effect doesn't reoccur.  Any ideas as to addressing this issue, or is it even an issue?