void TextEditor_MimeTypeChanged(object sender, EventArgs e)
 {
     textEditorImpl.ClearTooltipProviders();
     foreach (var extensionNode in allProviders)
     {
         if (extensionNode.IsValidFor(MimeType))
         {
             textEditorImpl.AddTooltipProvider((TooltipProvider)extensionNode.CreateInstance());
         }
     }
 }