++++attachMovie复制多个元件有关问题奇怪有关问题+++++++

++++attachMovie复制多个元件问题奇怪问题+++++++
用attachMovie复制多个元件,刚开始加载加载时,通过一个循环,可以顺立复制多个MC,
但当加载完毕后,通过按纽再动态复制时,只能复制一个元件,不能复制多个,每次复制时,原先attachMovie的元件被替换了.

此代码在时间轴上初始加载时运行,可以成功attachMovie多个元件:
for   (var   i   =   0;   i <counts;   i++)   {
      var   tmp_mc   =   _root.attachMovie( "objcontainer ",   "obj2 "+i,   this.getNextHighestDepth());
      //初始化
      tmp_mc.img   =   childnodes[i].firstChild.firstChild.nodeValue;
tmp_mc._x   =   childnodes[i].firstChild.nextSibling.attributes.x;
tmp_mc._y   =  
....
}

此代码按纽点击时触发的函数,原来想每次点击几下,复制几个元件,但运行时只能attachMovie出一个元件,原来点击attachMovie出来的元件被替换,而不是重新attachMovie出一个新的元件.
_global.addObject   =   function(img:String):Void     {

counts++;
var   tmp_mc   =   _root.attachMovie( "objcontainer ",   "obj2 "+counts,   depth);
                  //初始化
tmp_mc.img   =   img;
tmp_mc._x   =   Math.random()*550;
tmp_mc._y   =   Math.random()*350;
                  ...

};

[解决办法]
var tmp_mc = _root.attachMovie( "objcontainer ", "obj2 "+counts, ++depth);