Ok, I've just thought of a workaround for you that is easy to implement and easy to roll back if/when the root cause is resolved.  When I tested this in my lab,  it only affected tabs within the same IE session.   So, surely we can just disable Tabs   In Tools | Internet Options Click Settings on the tab section  [IMAGE]  Then uncheck "Enable Tabbed Browsing" [IMAGE]  Got to be worth a go for $5k/month 
We have Windows 2008 R2 servers which install Media player 12 as part of the desktop experience.  I have not found any way to put on media player 10 or 11 on these machines  (not suprisingly) Unfortunately the vworkspace client only supports media player 10 which was created in 2004, replaced with media player 11 in 2006   the media playing does seem to work, but it stays on top the other IE windows and so you can't use the browser at all, you need to use a different browser.  What this means is essentially a couple stupid little websites are about to cost me a $5k/month client so any suggestions or idea's at all are greatly appreciated.
Microsoft Media Player redirection