title: How to solve the problem that can't select project using Omni Sharp on VS Core?
body: <p>When I use the Omni Sharp to choose a project on VS Code, it occurs an error as follow:</p>
  <pre><code> Command 'OmniSharp: Select Project' resulted in an error (Extension 'ms-dotnettools.csharp'CANNOT use API proposal: quickPickSeparators. 
  lts packagejson#enabledApiProposals-property declares: [] but NOT quickPickSeparators.The missing proposal MUST be added and you must start in extension development mode or use the following command line switch:--enable-proposed-api ms-dotnettools.csharp)   
  </code></pre>
  <p><a href="https://i.stack.imgur.com/CmwYJ.png" rel="noreferrer">enter image description here</a></p>
  <p>How can I fix the error?</p>