title: EF 4.1 Code First error - The entity type SomeType is not part of the model for the current context
body: <p>While working with EF code first I get error given below at different times:</p>
  
  <p><em>The entity type SomeType is not part of the model for the current context.</em></p>
  
  <p>What are the possible causes of this error?</p>