When I press F5 the project compiles, and the new web page launches. However, the silverlight control loads (the standard load counter counts to 100%) but then the whole control just disappear. Only the left default menu bar (feedback etc) is visible. It's a very small project, my first actually. This also happened earlier today, but then I removed each thing one at a time and found that it was some radio buttons that caused it. I deleted them and remade them and it ran fine again. Now the same thing happened again, but it is something else, not sure yet. The question is; is this a familiar bug or am I just doing something wrong? My code-behind consist mostly of visibility changes, around 20 lines of code.