Adding a single Sprite on the main moviclip, Sprite remains invisible -- why?

1

I created a new AS3 document (550px by 400px) and added the following code to the first frame.

However, when I run this, I see nothing painted on the screen at all, the screen remains completely white.

Any ideas why ?


var m = new Sprite();
m.width = 200; 
m.height = 200;
//uncommenting makes no difference either
//m.stageHeight = 200;
//m.stageWidth = 200;
m.x = 0;
m.y = 0;
addChild(m);
m.graphics.beginFill(0xff0000);
m.graphics.drawRect(0, 0, 100, 50);
m.graphics.endFill();
trace("is sprite visible: " + m.visible);