I have a base class, defined as below (I'm also using DevExpress components): public abstract partial class BaseFormClass<R> : XtraForm where R : DataRow { ... } Contrary to what I've read from elsewhere, I'm still able to design this class. I didn't have to create a concrete class from it to do so. But, when I create a concrete class descended from it (as below), that class won't work in the designer. public partial class ConcreteFormClass : BaseFormClass<StronglyTypedRow> { ... } I get this message: The designer could not be shown for this file because none of the classes within it can be designed. The designer inspected the following classes in the file: ConcreteFormClass --- The base class 'BaseFormClass' could not be loaded. Ensure the assembly has been referenced and that all projects have been built. Has anyone seen this before? Any sort of known workaround?