[AlexCooper]

import flash.events.MouseEvent;
 
addEventListener(MouseEvent.MOUSE_DOWN, clickManager );
addEventListener(MouseEvent.MOUSE_UP, clickManager );
 
var shapeType:String = 'ellipse';
 
work_place.mouseChildren = false; // контейнер для рисования
 
function clickManager(e:MouseEvent):void {
 
	switch (e.target.name) {
		case 'ellipse_btn': shapeType = 'ellipse'; break;
		case 'rect_btn': shapeType = 'rectangle'; break;
		case 'work_place': (e.type=='mouseDown') ? addEventListener(MouseEvent.MOUSE_MOVE, makeShapes) 
												: removeEventListener(MouseEvent.MOUSE_MOVE, makeShapes); 
		break;
		default: trace('unregister target object');
	}
}
 
function makeShapes(e:MouseEvent):void {
 
	var color:uint = Math.random() * 0xFFFFFF;
 
	var shape:*;
 
	switch (shapeType) {
 
		case "ellipse": {
			shape = new Ellipse(10, 10, color);
		} break;
 
		case "rectangle": {
			shape = new Rect(5, 15, color);
		} break;
 
		default: return void;
	}
 
	work_place.addChild(shape);
 
	shape.x = mouseX;
	shape.y = mouseY;
	shape.cacheAsBitmap = true;
}

Добавлено через 3 минуты
Набросал очень быстро потому возможно нужно заменить

case 'work_place':

на

default: