anchor.diff:  
     @override
     void deactivate() {
  +    _markdown.deactivate();
       super.deactivate();
  -    _markdown.deactivate();
     }
   
     @override
  
positive.code: }
  
  class MarkdownEditor extends TextEditor {
    static bool isMarkdownFile(workspace.File file) => file.name.toLowerCase()
        .endsWith('.md');
  
    Markdown _markdown;
    StreamSubscription _markdownOnDirtySubscription;
    MarkdownEditor._create(AceManager aceManager, workspace.File file,
      SparkPreferences prefs) : super._create(aceManager, file, prefs) {
         _markdown = new Markdown(element, file);
  
negative.code:     ace.Mode.extensionMap['cmd'] = ace.Mode.BATCHFILE;
      ace.Mode.extensionMap['diff'] = ace.Mode.DIFF;
      ace.Mode.extensionMap['lock'] = ace.Mode.YAML;
      ace.Mode.extensionMap['nmf'] = ace.Mode.JSON;
      ace.Mode.extensionMap['project'] = ace.Mode.XML;
  
      _setupOutline(prefs);
  