title: "the entity type is not part of the model for the current context" error is thrown when project contains more than one EDMX file
body: <p>I'm using database first and I have a <code>switch</code> statement that looks something like this:</p>
  
  <pre><code>switch (site)
  {
      case Site.One:
          using (OneContext one = new OneContext())
              return one.OrganizationObjects.SingleOrDefault(x =&gt; x.u_Name == orgName)?.g_org_id;
      case Site.Two:
          using (TwoContext two = new TwoContext())
              return two.OrganizationObjects.SingleOrDefault(x =&gt; x.u_Name == orgName)?.g_org_id;
      default:
          throw new NotImplementedException();
  }
  </code></pre>
  
  <p>Both databases are pretty similar and have almost the all of the same models.</p>
  
  <p>If I delete the "Two" EDMX file and comment out the condition, then OneContext works perfectly. <br> If I add the TwoContext EDMX file to the project and run the code again, the "OneContext" code fails when it tries to query <code>OrganizationObjects.</code></p>
  
  <p>I made sure each context was using the correct connection string, but this error still occurs:</p>
  
  <p><a href="https://i.stack.imgur.com/6oQN9.png" rel="noreferrer"><img src="https://i.stack.imgur.com/6oQN9.png" alt="enter image description here"></a></p>