code: function() {
          var me = this,
              showCheck = me.showHeaderCheckbox !== false;     
  
          return {
              isCheckerHd: showCheck,
              text : '&#160;',
              width: me.headerWidth,
              sortable: false,
              draggable: false,
              resizable: false,
              hideable: false,
              menuDisabled: true,
              dataIndex: '',
              cls: showCheck ? Ext.baseCSSPrefix + 'column-header-checkbox ' : '',
              renderer: Ext.Function.bind(me.renderer, me),
              editRenderer: me.editRenderer || me.renderEmpty,
              locked: me.hasLockedHeader()
          };
      }
docs: Retrieve a configuration to be used in a HeaderContainer.
  This should be used when injectCheckbox is set to false.