How put Form above all elements in VerticalLayout

I have stuffed
VerticalLayout
. When I click
addButton
, I want to put
Form addForm
above all elements in
VerticalLayout
.

[i]

public class EventView extends VerticalLayout implements ComponentContainer,
Property.ValueChangeListener, Button.ClickListener, FormFieldFactory {

private EntityContainer<EventVdma> container;
private PagedTable table;

// private Object visibleFormProperties;
private Button addButton;
private Button deleteButton;
private Button editButton;
private Button saveButton;
private Button cancelButton;
private Panel toolBarPanel;
private Panel editPanel;
private Form editorForm;
private Form addForm;
}
[/i]

How to do that ???

How about verticalLayout.addComponentAsFirst(addForm); ?