code: function(pos, direction, e, preventWrap, verifierFn, scope) {
          if (direction == 'left') {
              direction = 'up';
          } else if (direction == 'right') {
              direction = 'down';
          }
          pos = Ext.view.Table.prototype.walkCells.call(this, pos, direction, e, preventWrap, verifierFn, scope);
          if (pos && !pos.column) {
              pos.column = 1;
          }
          return pos;
      }
docs: Custom implementation of walkCells which only goes up and down.