code: function _setCurrentFile(newFilename) {
          var oldFilename = currentFilename;
          if (oldFilename === newFilename) {
              return;
          }
          currentFilename = newFilename;
          _toggleProjectScope();
          PreferencesImpl.manager.signalContextChanged(_buildContext(oldFilename, currentLanguageId),
                                                       _buildContext(newFilename, currentLanguageId));
      }
docs: @private
  
  This is used internally within Brackets for the EditorManager to signal
  to the preferences what the currently edited file is.
  
  @param {string} newFilename Full path to currently edited file