anchor.diff:    List<Resource> _filteredFiles;
     // Sorted children of nodes.
     Map<String, List<String>> _filteredChildrenCache;
  +  // Expanded state when no search filter is applied.
  +  List<String> _currentExpandedState;
   
     FilesController(this._workspace,
                     this._actionManager,
  
positive.code:     if (_filterString == null) {
        _filteredFiles = null;
        _filteredChildrenCache = null;
        _reloadData();
      } else {
        Set<String> filtered = new Set();
        _filteredFiles = [];
  
negative.code:   }
  
    void treeViewSaveExpandedState(TreeView view) {
      if (_filterString != null) return;
      _currentExpandedState = _treeView.expandedState;
      localPrefs.setValue('FilesExpandedState',
          JSON.encode(_treeView.expandedState));
    }
  