When i select a item under the root navigation the list jumps to te left and the click is not always goes to the webpage. See the screenshot.
It works for me using IE8 on winxp. what is your exact IE version and OS?
ie8 on vista with piwik 0.8
this also happend with 0.7
so the problem probably only happens on Vista. I don't have vista so I can't fix/replicate unfortunately.