Border on left navigation incorrect in FF 3.6.28 and Opera 10.10

Created an attachment (id=8044)
Border of the left nav is not drawn properly - Opera 10.10

The border around the navigation bar on the left is not drawn correctly in Firefox 3.6.28 and Opera 10.10, or earlier versions.

See the attached screen shot, and notice the border seem to be drawn as a single vertical line.

Note that various older versions of these browser are listed in the goldenapps and available in the ReactOS downloader, which people will test under ReactOS. ReactOS.org should look more or less correct in these browsers.