code: function _close(paneId, file, optionsIn) {
          var options = optionsIn || {};
          _forEachPaneOrPanes(paneId, function (pane) {
              if (pane.removeView(file, options.noOpenNextFile) && (paneId === ACTIVE_PANE || pane.id === paneId)) {
                  _removeFileFromMRU(pane.id, file);
                  exports.trigger("workingSetRemove", file, false, pane.id);
                  return false;
              }
          });
      }
docs: Closes a file in the specified pane or panes
  @param {!string} paneId - id of the pane in which to open the document
  @param {!File} file - file to close
  @param {Object={noOpenNextFile:boolean}} optionsIn - options
  This function does not fail if the file is not open