code: function getSelectedItem() {
          // Prefer file tree context, then file tree selection, else use working set
          var selectedEntry = getFileTreeContext();
          if (!selectedEntry) {
              selectedEntry = model.getSelected();
          }
          if (!selectedEntry) {
              selectedEntry = MainViewManager.getCurrentlyViewedFile();
          }
          return selectedEntry;
      }
docs: Returns the File or Directory corresponding to the item selected in the sidebar panel, whether in
  the file tree OR in the working set; or null if no item is selected anywhere in the sidebar.
  May NOT be identical to the current Document - a folder may be selected in the sidebar, or the sidebar may not
  have the current document visible in the tree & working set.
  @return {?(File|Directory)}