The EditorAttribute of the PropertyGrid currently requires the control type to be available for the class defining the attribute. In the original .NET Property Grid, the EditorAttribute supported a constructor with a string which allowed the type to be resolved at runtime rather than compile time. The TypeConverter attribute also has this type name signature available. This is particularly useful when architecting a solution where the model libraries shouldn't reference the views.
The functionality could be added with a simple constructor signature like this:
public EditorAttribute(string editorTypeName)