I have a strange problem with the design time in a VS2013 project. It's not present in VS2010 with the same setup.
When I add the UI components to my forms everything seems normal, but as soon as I close my project and reopen it I'm presented with the following error:
This happens when I target .NET Framework 3.5 instead of the default 4.5 in this VS version. There's no problem compiling the project, and everything works in the deployed version. It's just a design time issue.
There's no problem with references or anything, and if I add a new form to my existing project the whole thing repeats itself. I can design and compile as much as I want, but I get the same error when I close/reopen.