Initially, everything was working fine for a couple of months. Recently, though, I've been consistently getting these exceptions when working in the XAML designer. When I first open an XAML document, the designer loads as usual, but once I click on a particular control, the exception is thrown. Reloading the designer does just that, but the exception is still thrown when clicking on that control. The message associated with the exception is:Value cannot be null.Parameter name: spOriginally, I thought this was only occurring with controls which were either custom controls or which I had applied a style to. However, some styled controls work fine in the designer, while other built in controls do not.I should note that my project compiles absolutely fine. No build errors are reported and the build succeeds. No exceptions are thrown at runtime, nor do I see any unexpected results in terms of styling and functionality.I have this problem on two separate PCs. Both run Visual Studio 2012 Professional. One PC runs Windows 8 Professional and the other Windows 8 Enterprise. Neither version of Windows 8 is a preview or RC, they both are the actual releases.I've attached the data from three logs in the Event Viewer for a particular occurrance.
Visual Studio/Team Foundation Server/.NET Framework Tooling Version
Steps to reproduce
Operating System Language