Shape Coordinate Problem

I’m new to ActionScript and could really use your help.

I’ve created a rectangle as such:
var filledBar:Shape = new Shape();
filledBar.graphics.beginFill(0x6699CC, 1);
filledBar.graphics.drawRect(300, 200, 50, 200);
addChild(filledBar);

Now I try to later change the height, as such:
filledBar.height = 300;

It seems to actually move my x/y coordinates in addition to changing the height. Why does it move the coordinates?

Also, when I do a trace of the coordinates after creating the rectangle, it shows up as 0,0 - even though I’ve set them to be 300,200 and that seems to be where it’s actually positioned. Could someone help me out with this issue? Thank you!