code: int getIndexOfChild(final WComponent childComponent) {
  		ComponentModel model = getComponentModel();
  		List<WComponent> children = model.getChildren();
  
  		return children == null ? -1 : children.indexOf(childComponent);
  	}
docs: Retrieves the index of the given child.
  
  @param childComponent the child component to retrieve the index for.
  @return the index of the given child component, or -1 if the component is not a child of this component.