I have inherited source code from a project. I am trying to decypher how it all fits together. It uses XAML. The problem is that when I open the XAML files, Visual Studio 2008 does not display it in Design Mode, and when it shows the file in text form, many of the elements seem to be undefined -- I mean, it is displayed with that red squigglie line unter the title of some of the XML tages -- like "UserDefined" and "Grid". I thought that if I install Expression Blend, it will have these elements defined. But this did not work. Any ideas? My first idea was that this was a Visual Studio 2008 issue and that it would work in the current Visual Studio 2010. But their are tabs that appear when I first open the XAML file for displaying the file graphically or as text. It defaults as text. But when I click to show it graphically, it shows an error window. I am viewing this in Visual Studio 2008 and I am loading a solutions file when I view this. But here is where it gets wierd. If I open the XAML file sepeately on another computer in Visual Studio 2010, it displays properly in Design mode. So what do I have on one computer that I am missing on the other one? And, yeah, I have asked this question in one way or another other places.