How to resolve VS2010 Windows Form Designer issue (base class could not be loaded)

Question

I have recently been getting an error in the Windows Forms designer of VS2010SP1 when using inherited UserControls.

The error is

The designer

Answer 1

I had this bug with VS2015, tried clean/rebuild steps, build in release didn't work.

I put the base control in another project and the designer complained that there wasn't a constructor for it. I had a constructor with 2 arguments, but no empty one. I added an empty constructor and the designer worked. I then moved the base control back in it's original location with the derived controls, and the designer bug came back.

I gave up and just put the base control in a "VsBug" project, seems to be happy...