Replace Canvas with Group!??

Question

Hi,
I tried to replace the Canvas with a group in the following code
This works fine:
1.)
<mx:TabNavigator id="tn" width="100%" height="100%"> ...
private function AddForm():void{
    var children:Array=tn.getChildren();
    var form:myCanvas=new myCanvas;
    tn.addChild(form);
    form.label="Form" + (children.length+1).toString();
    tn.selectedChild=form;
2.)
I tried to do the same with a group, this have several problems:
private function AddGroup():void{
    var children:Array=tn.getChildren();
    var form:myGroup=new myGroup;
    tn.addChild(form);
          // runtime: TypeError: Error #1034: Type Coercion failed: cannot convert myGroup@f02ec29 to mx.core.Container.
    form.label="Form" + (children.length+1).toString();
          // compile error 1119: Access of possibly undefined property label through a reference with static type myGroup.    TestModuleService.mxml              TestModuleService/src    line 78    Flex Problem
    tn.selectedChild=form;
          //compile error 1067: Implicit coercion of a value of type myGroup to an unrelated type mx.core:Container.    TestModuleService.mxml              TestModuleService/src    line 80    Flex Problem
Is it possible to achieve the same result as 1.) using a group?
Thanks for any pointers!
Martin Zach

Answer 1

Hi,
the reason for my question was, that I didn't understand the advantage of spark. Now I do!
The follwoing videos explains that wunderfully:
http://labs.adobe.com/technologies/flashbuilder4/tutorials/
->
Part "Learn about Flex 4 SDK"
Video: Skinning Components and Applications in Flex 4
Thanks for your answers!
Martin Zach