code: function setFileViewFocus(fileSelectionFocus) {
          if (fileSelectionFocus !== PROJECT_MANAGER && fileSelectionFocus !== WORKING_SET_VIEW) {
              console.error("Bad parameter passed to FileViewController.setFileViewFocus");
              return;
          }
  
          if (_fileSelectionFocus !== fileSelectionFocus) {
              _fileSelectionFocus = fileSelectionFocus;
              exports.trigger("fileViewFocusChange");
          }
      }
docs: Modifies the selection focus in the project side bar. A file can either be selected
  in the working set (the open files) or in the file tree, but not both.
  @param {String} fileSelectionFocus - either PROJECT_MANAGER or WORKING_SET_VIEW