message: feat: Add groupTargetElement
diff: import React from "react";
  -import { refs } from "framework-utils";
  +import { refs, ref } from "framework-utils";
  import MoveableGroup from "../MoveableGroup";
  import MoveableManager from "../MoveableManager";
  +import { prefix } from "../utils";
  export default {
  name: "groupable",
  @@ -12,7 +13,7 @@ export default {
  const { left, top } = moveable.state;
  const position = { left, top };
  - return targets.map((target, i) => {
  + return [...targets.map((target, i) => {
  return <MoveableManager
  key={i}
  ref={refs(moveable, "moveables", i)}
  @@ -20,6 +21,8 @@ export default {
  origin={false}
  parentMoveable={moveable}
  parentPosition={position} />;
  - });
  + }),
  + <div key="groupTarget" ref={ref(this, "groupTargetElement")} className={prefix("group")} />,
  + ];
  },
  };
  