code: function() {
  			var aVisibleColumnsIds = [],
  			aColumns = SelectionUtils.treeTable.getColumns();
  
  			aColumns.forEach(function (oColumn) {
  				if (oColumn.getVisible()){
  					aVisibleColumnsIds.push(oColumn.sId);
  				}
  			});
  
  			storage.setVisibleColumns(aVisibleColumnsIds);
  		}
docs: Persist visible columns selection in local storage.