code: public void add(CollapsiblePanel collapsiblePanel, int weight) {
  	if (panels.contains(collapsiblePanel) == false) {
  	  collapsiblePanel.weightY = Math.max(0, weight);
  	  panels.add(collapsiblePanel);
  	  super.add(collapsiblePanel);
  	}
    }
docs: Adds a {@link CollapsiblePanel} to the container. The order of the
  components inside the container is from top to bottom.
  
  @param collapsiblePanel
  the {@link CollapsiblePanel} to be added
  @param weight
  the weight for the {@link CollapsiblePanel} in a fill mode.
  <P>
  Value 0 disables the fill, the height's component is defined for
  his preferred size.