code: function updateColumns(item, newColumns) {
    item._tableStructure.columns = newColumns;
    if (item._tableStructure.columns.length === 0) {
      // Nothing to show, so the attempt to redraw will fail; need to explicitly hide the existing regions.
      item._regionMapping.hideImageryLayer();
      item.terria.currentViewer.notifyRepaintRequired();
    }
    // Close any picked features, as the description of any associated with this catalog item may change.
    item.terria.pickedFeatures = undefined;
  }
docs: Sets the tableStructure's columns to the new columns, redraws the map, and closes the feature info panel.