webix UI v.4.1.0 (file webix_debug.js line 11139 - 11144)
if (typeof obj == "object") // true
id = obj.id || webix.uid(); // obj.id is null
else /* suggest to remove this line maybeee */
obj = { id:id, value:id };
this.order.push(obj.id); // null
if (this._scheme_init)
this._scheme_init(obj);
this.pull[obj.id] = obj; // only one thing this.pull.undefined => the last obj