title: Entity Framework 4 mapping fragment error when adding new entity scalar
body: <p>I have an Entity Framework 4 model-first design. I create a first draft of my model in the designer and all was well. I compiled, generated database, etc.</p>
  
  <p>Later on I tried to add a string scalar (Nullable = true) to one of my existing entities and I keep getting this type of error when I compile:</p>
  
  <blockquote>
    <p>Error 3004: Problem in mapping
    fragments starting at line 569: No
    mapping specified for properties
    MyEntity.MyValue in Set MyEntities. An
    Entity with Key (PK) will not
    round-trip when:   Entity is type
    [MyEntities.MyEntity]</p>
  </blockquote>
  
  <p>I keep having to manually open the EDMX file and correct the XML whenever I add scalars.</p>
  
  <p>Ideas on what's going on?</p>