//var chx = this.getChildAt(0)
//var chy = this.getChildAt(1)
//var chz = this.getChildAt(2)
//this.numChildren
3
//this.addChild(chx)
//chy === this.getChildAt(0)
true
//chz === this.getChildAt(1)
true
//chx === this.getChildAt(2)
true
//this.numChildren
3
//Removed symbol "chz" in timeline
//chy === this.getChildAt(0)
true
//chx === this.getChildAt(1)
true
//this.numChildren
2
//Removed symbol "chy" in timeline
//chx === this.getChildAt(0)
true
//this.numChildren
1
//Removed symbol "chx" in timeline
//chx === this.getChildAt(0)
true
//this.numChildren
1
//Re-added symbol "chx" in timeline
//chx === this.getChildAt(0)
true
//chx === this.getChildAt(1)
false
//this.numChildren
2
//Re-added symbol "chy" in timeline
//chx === this.getChildAt(0)
true
//chx === this.getChildAt(1)
false
//chx === this.getChildAt(2)
false
//this.numChildren
3
//Re-added symbol "chz" in timeline
//chx === this.getChildAt(0)
true
//chx === this.getChildAt(1)
false
//chx === this.getChildAt(2)
false
//chx === this.getChildAt(3)
false
//this.numChildren
4
