Microsoft Silverlight  4.0.50524
All updates to Microsoft Silverlight include functional, performance, reliability and security improvements and are backward compatible with web applications built using previous versions of Silverlight.
- Fixes issues when using PlayReady® on certain Mac and Windows configurations.
- Fixes an issue where an AmbiguousMatchException exception occurs running on certains Silverlight 3.0 applications.
- Fixes memory leak issues on Mac which occur playing streaming media for long periods of time.
- Fixes an issue on Mac where the TAB key does not start the Control.KeyDown event as expected.
- Fixes an issue on Mac when you set the full-screen mode for a Silverlight application that is running on a secondary monitor, the screen is positioned incorrectly.