function addDefaultStyleToProtoChain(chain):Object {
    // If there's a defaultFactory for this style sheet,
    // then add the object it produces to the chain.
    if (defaultFactory != null)
    {
        var originalChain:Object = chain;

        // from here on...
        defaultFactory.prototype = chain;
        chain = new defaultFactory();
        defaultFactory.prototype = null;
     }

     return chain;
  }

var o:Object = new defaultFactory();
   trace(o) // {fontFamily:Arial, color:blue};
   trace(chain) // {color:red, fontWeight:bold}

   defaultFactory.prototype = chain;
   chain = new defaultFactory();
   trace(chain) // ???

// create a function that returns an object
var myDynamicDefinition:Function = function() {
    this.name = "initialvalue";
    trace('this.name='+this.name); // returns this.name=initialvalue
}

var dynamicDefinitionInstance = new myDynamicDefinition(); // create an instance of myDynamicDefinition
trace(ObjectUtil.toString(dynamicDefinitionInstance));// returns name = "initialvalue"

// create a new definition and assign it to our dynamic definitions
var newDefinition = {color:"red", name:"newObjectValue"};
myDynamicDefinition.prototype = newDefinition;

// create a new instance with new definition
var dynamicDefinitionInstance2 = new myDynamicDefinition();  // create an instance of myDynamicDefinition
trace(ObjectUtil.toString(dynamicDefinitionInstance2)); // returns name = "initialvalue" color = "red"

// delete name property instance
delete dynamicDefinitionInstance2.name;
trace(ObjectUtil.toString(dynamicDefinitionInstance2)); // returns name = "newObjectValue" color = "red"

// set prototype to null
myDynamicDefinition.prototype = null;

// create a new instance
var dynamicDefinitionInstance3 = new myDynamicDefinition();
trace(ObjectUtil.toString(dynamicDefinitionInstance2)); // returns name = "newObjectValue" color = "red"

newStyleDeclaration.defaultFactory = function():void
{
    leftMargin = 50;
    rightMargin = 50;
}

var def : Function = function() {
        this.someDefChanges = "someDefChanges";
    }

    var o1 = {testValueO2 : "testValueO2"};
    def.prototype = o1;
    var o2 = new def();
    def.prototype = null;

    // o1 = {testValueO2: "testValueO2"}
    // o2 = {someDefChanges: "someDefChanges", testValueO2: "testValueO2"}