title: Why there are both EntityFramework and System.Data.Entity assemblies in my project?
body: <p>I just opened VS 2012 and created a class library project. After that I added a new <code>ADO.NET Entity Data Model</code> item to my solution.</p>
  
  <p>I noticed there are both an assembly called EntityFramework 5.0 and another one called System.Data.Entity 4.0. Shouldn't it be just one?</p>
  
  <p>As a bonus problem, when I click the file the designer crashes:</p>
  
  <pre><code>Error   2   Error 6039: warning CS1701: Assuming assembly reference 'System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' matches 'System.Data.Entity, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089', you may need to supply runtime policy
  c:\Users\andre_pena\AppData\Local\Temp\5srvr0ge.0.cs(465,29) : error CS1061: 'System.Data.Metadata.Edm.EdmFunction' does not contain a definition for 'IsComposableAttribute' and no extension method 'IsComposableAttribute' accepting a first argument of type 'System.Data.Metadata.Edm.EdmFunction' could be found (are you missing a using directive or an assembly reference?)    c:\users\andre_pena\documents\visual studio 2012\Projects\ClassLibrary2\ClassLibrary2\Model1.edmx   1   1   ClassLibrary2
  </code></pre>
  
  <p>Is it everything ok with my system? Is the existence of both files normal? Why am I getting this error?</p>