Announcing the immediate availability of the Silverlight Spy December 2012 Update. This maintenance release fixes a number of user interface issues that occur after installing .NET Framework 4.5. Installing .NET 4.5 includes an in-place upgrade of the core .NET 4.0 assemblies having a set of updated WPF styles. Those new styles interfered with Silverlight Spy and this release addresses these issues.
Furthermore Silverlight Spy now correctly identifies Silverlight 5 Update 1 and the Windows Phone 7.1.1 SDK update.
If you are looking for Windows Phone 8, Windows Store and WPF support you probably want to take a look at XAML Spy, the successor of Silverlight Spy.
Get the latest release of Silverlight Spy from the download page.