Geometry Calculations

• Changing the preferred size of an object does not change its size, or trigger any geometry negotiation e.g. resetting the label of a Button does not change the size
• Changing the preferred size of an object automatically invalidates it.
• To force a size recalculation for invalid children of a Container call layout() on the Container.
• This will force a resize each time the label is reset:

  class AutoResizeButton extends Button {
      public void setLabel(String name) {
          super.setLabel(name);
          getParent().layout();
      }
  }
  

  (See GrowMe.java)