title: Auto completion of classes from another project in the same solution doesn't work
body: <p>I will reformulate my question because Visual Studio 2019 updated and the problem is back.</p>
  <p>Here's the problem:</p>
  <p>In my solution, I have 2 projects. The first one, let's say P1, is a vb.net class library. The second, P2, is a normal C# windows application.</p>
  <p>P1 references are added in P2 and I can successfully use P1's classes in my P2.</p>
  <p>BUT, the auto completion and Intellisense doesn't see the P1 classes.</p>
  <p>Problems encountered :</p>
  <ul>
  <li>No autocompletion</li>
  <li>Can't navigate to symbol under the caret</li>
  <li>Errors within these lines of code where a class of P1 is used doesn't show up in the Error List (but prevent building project)</li>
  <li>No colors in the code (See images)</li>
  </ul>
  <p>What I have
  <a href="https://i.stack.imgur.com/8yRYb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8yRYb.png" alt="enter image description here" /></a>
  What I want (Ignore the theme)
  <a href="https://i.stack.imgur.com/Nr6dt.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Nr6dt.png" alt="enter image description here" /></a></p>
  <p>I hope this is enough information. Thanks for the help.</p>