code: function(oDD, sGroup) {
              if (!this.ids[sGroup]) {
                  this.ids[sGroup] = {};
              }
  
              var obj = this.ids[sGroup];
              if (obj && obj[oDD.id]) {
                  delete obj[oDD.id];
              }
          }
docs: Removes the supplied dd instance from the supplied group. Executed
  by DragDrop.removeFromGroup, so don't call this function directly.
  @method removeDDFromGroup
  @private
  @static