We are noticing some very strange behavior on an installation of a .NET2-based webapp on Server 2008. Our app uses "old school" Integrated Windows Authentication and simply reads the LOGIN_USER server variable from the request collection. There's a good reason for this, but that's somewhat irrelevant to the question, since the underlying WindowsAuthentication code from ASP.NET does the same thing.

Anyway...

• When you enter the URL in the browser, it loads up just fine and displays the username (from LOGIN_USER) no problem.
• When you click on a link within the web app, it loads the page just fine and authenticates without any problems.
• When you "hard refresh" (Ctrl-F5) it also works just fine.
• However, when you click "open in a new window" or "open in a new tab", the LOGON_USER variable is blank

Any ideas? Am I missing some IIS7 setting somewhere?

Tested clients are Windows 7 with IE8 or Windows XP with IE6.