title: Why are some YAML keys and values highlighted oddly?
body: <p>In Visual Studio Code (1.22.2) when I add certain words to a YAML file they are syntax highlighted differently to what is expected.</p>
  
  <p>For example both <code>on</code> and <code>y</code> are colored orange here. AFAIK, neither <code>on</code> nor <code>y</code> have any special YAML significance. This occurs for other keys and values also. I note this same color is used on <em>values</em> of <code>true</code> or <code>false</code> but here it is occurring for seemingly arbitrary values and also for keys. The same occurs after a restart with all extensions disabled so it's not some forgotten extension I don't think.</p>
  
  <p><a href="https://i.stack.imgur.com/AdOkf.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/AdOkf.png" alt="screen grab of syntax highlighted text in vscode"></a></p>
  
  <p>Is this some other file-type syntax-highlighter interfering? Am I missing something about YAML 'keywords'?</p>