var button : JButton = new JButton("click");
  button.setSize( 100,25 );
  button.setLocation( 100, 100 );
  
  var label1 : JLabel = new JLabel("avoid resizing");
  label1.setSize(100, 25);
  label1.setLocation( 200, 50 );
  
  var label2 : JLabel = new JLabel("ok for resizing");
  label2.setSize(100, 25);
  label2.setLocation( 50, 50 );
  label2.setOpaque( true );
 
  try
  {
   // Direct affectation
   var resizer : ResizerController = ResizerController.init( button );
   
   // Simple call to #init method
   ResizerController.init( label1 );
   ResizerController.init( label2 );
  }
  catch( e : Error )
  {
   // log error message
  }
  
  //We can retreive ResizerController for a specific component like :
  var labelResizer : ResizerController = ResizerController.getController( label1 );
  labelResizer.setResizable( false );
  
  resizer.setResizeDirectly( true );
  
  // content must have a layout set to EmptyLayout to allow correct resizing
  content.append( button );
  content.append( label1 );
  content.append( label2 );
 

Many thanks Romain Ecarnot, this class is based on his ResizerController, and all resizer implement are inspired by him.