text: Good point besides the general sizing/measuring I am wasting the rest... it simplifies it
  a little too. I don't use the spacers often, but I do use them to solve quick layouts for
  clients who must have a things displayed in a certain way.
  Class:
  //Declare package.
  package spark.components
  {
  import spark.primitives.supportClasses.GraphicElement;
  //Create child class of the GraphicElement class.
  public class Spacer extends GraphicElement
  {
  //----------------------------------------
  // Constructor
  //----------------------------------------
  public function Spacer()
  {
  super();
  }
  }
  }
  -Mark
  -----Original Message-----
  From: Maxime Cowez [mailto:maxime.cowez@gmail.com]
  Sent: Friday, December 21, 2012 10:50
  To: flex-dev@incubator.apache.org
  Subject: Re: [Component] Spacer
  @Mark Instead of Rect, you'd better use GraphicElement directly (Rect
  extends FilledElement extends StrokedElement extends GraphicElement). I
  suppose the performance should be better than that of mx:Spacer because
  that inherits from UIComponent and GraphicElement does not. Though I think
  the gain would be marginal since you typically don't use Spacers all over
  the place.
  That said, I remember some discussion on this list on the topic of
  composing behaviours into components rather than inheriting them. A Spacer
  would in that case only have the measuring/sizing behaviour and nothing
  more. Don't know whether anyone has made any progress in this field though.
  @Jeffry I suppose that in time we may want to drop the mx components or at
  least give a developer the option to only target the Spark component set.
  In that case, you would require a complete Spark component set, containing
  even such trivial components like a Spacer.