title: Core 2 Tag Helpers not showing in the editor, even after multiple VS reinstalls.
body: <p>For anyone that doesn't already know what a tag helper is. This is what a tag helper is. </p>
  
  <pre><code>&lt;input asp-for="Forename" class="form-control" /&gt;
  </code></pre>
  
  <p>Previously, when I begun typing "asp-for" intelisense would suggest all the properties of the model. As you can imagine, this was extremely useful. 
  However, not only has intelisense stopped working, but Visual Studio seems to have completely forgotten that tag helpers exist. </p>
  
  <p>Previously, these tag helpers were shown in green, and they would be flagged up as errors if the property you'd used, for example, did not exist. </p>
  
  <p>Now, I have no such luck. Visual studio now just renders them the same it would any other HTML element. </p>
  
  <p><strong>How they look now:</strong></p>
  
  <p><a href="https://i.stack.imgur.com/FHCRM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FHCRM.png" alt="enter image description here"></a></p>
  
  <p><strong>How they should look:</strong> (taken on another computer)</p>
  
  <p><a href="https://i.stack.imgur.com/jHIoM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jHIoM.png" alt="enter image description here"></a></p>
  
  <p><strong>Importantly</strong> these tag helpers -do- work. The ones that I wrote before the problem work fine, and if I manually and very carefully copy paste the names of the model properties over, they work fine too. This is just an extremely inefficient way of doing it, and makes things hard to debug when something goes wrong. </p>
  
  <p><strong>Additional Information</strong></p>
  
  <ul>
  <li>This is not a code problem. This is a project, and everyone is using the same project. It works perfectly for them</li>
  <li>I have reinstalled the ASP.NET stuff in the VS installer, I have "repaired" my install of Visual Studio, then I reinstalled Visual Studio by uninstalling it and reinstalling. I have <strong>no</strong> plugins running.</li>
  <li>Another bizarre factor here is that this problem started out intermittent, being fixed when I closed and re-opened the project, then being fixed when I restarted the computer, and then eventually not working at all, ever. </li>
  </ul>