When creating a new object there is no auto completion when trying to access properties or methods of it in the same line. For example: var rightSide:Number = new Rectangle(-100,-100,300,300).right; In this example, you wouldn't get any autocompletion or hints after typing new Rectangle(-100,-100,300,300). This seems like an unlikely scenario, but it comes into play more with custom classes (as opposed to native AS3 code as in the example above), such as creating a tween: new NanoTween(mySprite, 1.0, {x:100, y:200}).start()