title: Cannot open edmx file - ADO.NET Entity Data Model Designer missing "Open With"
body: <p>I'm using VS 2008, Service Pack 1. Cannot open edmx file in ADO.NET Entity Data Model Designer. When click open with I don't have even options to open with it.</p>
  
  <p>The interesting thing it was working fine before.</p>
  
  <p>I reinstalled service pack, reset settings - didn't help.</p>
  
  <p>Any ideas how to fix it?</p>