code: function(column) {
          var result = column.width || 0,
              subcols, len, i;
  
          // <debug>
          if (column.flex) {
              Ext.Error.raise("Columns which are locked do NOT support a flex width. You must set a width on the " + column.text + "column.");
          }
          // </debug>
          if (!result && column.isGroupHeader) {
              subcols = column.items.items;
              len = subcols.length;
              for (i = 0; i < len; i++) {
                  result += this.getColumnWidth(subcols[i]);
              }
          }
          return result;
      }
docs: Used when calculating total locked column width in processColumns Use shrinkwrapping of child columns if no top level width.