anchor.diff:    bool _active = false;
   
     AceEditorTab(EditorArea parent, this.provider, this.editor, Resource file)
  -    : super(parent, file) {
  +      : super(parent, file) {
       page = editor.element;
       editor.onModification.listen((_) => parent.persistTab(file));
     }
  
positive.code:  * Manages a list of open editors.
   */
  class EditorArea extends TabView {
    static final RegExp _imageFileType =
        new RegExp(r'\.(jpe?g|png|gif|ico)$', caseSensitive: false);
  
    final EditorProvider editorProvider;
    final Map<Resource, EditorTab> _tabOfFile = {};
  
    final Workspace _workspace;
  
    bool _allowsLabelBar = true;
  
    StreamController<String> _nameController = new StreamController.broadcast();
  
    EditorArea(Element parentElement,
               this.editorProvider, this._workspace,
               {bool allowsLabelBar: true})
        : super(parentElement) {
      onClose.listen((EditorTab tab) => closeFile(tab.file));
      this.allowsLabelBar = allowsLabelBar;
      showLabelBar = true;
  
      _workspace.onResourceChange.listen((ResourceChangeEvent event) {
        // TODO(dvh): reflect name change instead of closing the file.
        event = new ResourceChangeEvent.fromList(event.changes, filterRename: true);
        for (ChangeDelta delta in event.changes) {
  
negative.code: 
    void _savePersistedTabs() {
      List<String> filesUuids = [];
      for (EditorTab tab in tabs) {
        if (tab.persisted) filesUuids.add(tab.file.uuid);
      }
  
  