TEdgeBrowser Popup menu / Context menu

The context menu can be deactivated using Javascript. This solution does not cover all use cases. It's enough for my problem..

<!DOCTYPE html>
<html lang="de">
  <head>
  <title>Test</title>
  <script type='text/javascript'>
    let ContextMenuDefault = false;  
    document.addEventListener('contextmenu', function(event)
    {
      if (false == ContextMenuDefault)
       event.preventDefault();
    }, true);
  </script> 
  </head>   
  <body>
   Hello World
  </body>
</html>