Hopefully folks saw the announcement about Silverlight 4 Service Release GDR1 availability. See Tim’s link here and KB2164913. The service release is being distributed by Microsoft Update as an Important update on Vista/Win7 and Critical update on Windows XP/ Windows 2003 Server. Mac and other Windows users who did opt-in for Microsoft Update will be prompted to install Silverlight 4 GDR1 soon after 9/1/2010.
In addition to other fixes (See above posts), this release fixes some key performance issues which I wanted to highlight: