Flash Builder: Why won't my mx:image show?

I have a very strange bug. I am trying to sort of take screenshots of an application and applying them to two (virtual) sides of a component. i am trying to accomplish this through creating two bitmaps (_front and _back) and setting them accordingly.开发者_如何学Python this is done in the applyImage method below. When i call this method from outside of the component, it works fine and i see my image. On the other hand, when i call applyImages from togglesides, it won't work. the image just won't show itself. When i trace the source of the _image, i can see the source is there, but it's just not showing.

Anyone know what might cause this? Could the problem be caused because i use mx:image in a spark-environment with a bitmap as source? (which I would find difficult to believe since i've never had problems with this before when just setting a url as source).

Thanks in advance.

public function applyImage(bitmap:Bitmap):void
{
    if(_isFront)_front = bitmap;
    else _back = bitmap;

    _image.source = "";
    _image.source = bitmap;
    _image.maintainAspectRatio = false;
    _image.mouseEnabled = false;
    _image.mouseChildren = false;

    _image.width = this.width;
    _image.height = this.height;
}

public function toggleSides():void
{
    if(_isFront){
        _isFront = false;
        applyImage(_back);
    }
    else{
        _isFront = true;
        applyImage(_front);
    }
}

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I have solved the problem by creating two images and changing their visibility, but i'm still not satisfied by this actually. I have to know what is causing this bug. So if anyone has a solution or an explanation to this bug, feel free to enlighten me :)