Just posted this blog to express some frustration on behalf of the Exchange technical community that Microsoft hasn’t been able to fix the problem that IE9 introduces for Exchange 2007 and Exchange 2010. Essentially, once IE9 is on a server or workstation that runs the Exchange Management Console (EMC), you end up with a situation that you can’t close EMC because it protests that some dialogs are open. The root cause seems to lie in some interaction between the underlying Microsoft Management Console (MMC) and IE9, but it’s just unacceptable that Microsoft has allowed the issue to linger for over four months.
Hopefully the protests will find their way to the ears of Windows and Exchange engineering management and they can sort this embarrassing fiasco out quickly.
– Tony
Thoughtsofanidlemind's Blog 
Totally agree that Microsoft of late seem to returning to the dark days and not paying enough attention to quality checks. It is unacceptable to have such a repeatable problem unaddressed for a significant amount of time. I’m not sure if IE9 was rushed to market too soon but it does appear a number of core MS applications have issues with the latest browser including SharePoint (MOSS/WSS3.0) and Exchange
+1