It's not because of VS. It's because the folder exists on disk. Go into Windows Explorer and delete the folder, then add it into VS.

BTW, all project files in VS are simply XML files. The filename is the same as the project with a .csproj or .vbproj extension. In VS, you can right-click on the project and select Unload, then right-click again to edit the file. When done, right-click and reload the project. Be careful spelunking into the project file.


>Another little issue I ran into. If I delete a folder from the VS project (e.g. Content), I cannot later add a folder of the same name. As if VS simply "marks" the folder as deleted but it is still somewhere. Anybody knows which file I need to hack to get rid of the folder name so that I can add it again?