Everybody that is doing XAML editing has hit this issue one moment in time – the editor is buggy. First of all – the designer is really useless. Second, if you keep editors open side-by-side you will eventually get a Visual Studio crash. Also from time to time you won’t be able to open the XAML file because apparently it is open but hidden. Finally, I would mention that the XAML editor is a lot slower than the other Visual Studio editors.