Typically when is the constructor of a component of a panel, page, etc called?

[Brown, Berlin [GCG-PFS]]

I was trying to get a feel for the wicket lifecycle, I can where
onBeforeRender, onAfterRender are  called during the component rendering
lifecycle.  But, I still don't see when the constructor (object
instantiation) of a component.   If I debug and/or trace the constructor
calls, it looks like the component is instantiated every time is
rendered?
 
With ajax components, when is the constructor of a component called?  In
my case below, when is the MyPanel constructor called.  Only once?  when
the object is added to the ajax tabbed panel.  Or when the content is
rerendered?

AjaxTabbedPanel ajaxTabbedPanel
...
 
public class MyPanel extends Panel {
 
   public MyPanel() {
     ... add components.
   }
 
}
 
....
new Page();
ajaxTabbedPanel.addTheMyPanelToAjaxPanel(new MyPanel));
thePage.add(ajaxTabbedPanel)
...
 
onClickOfTab {
  target.addComponent(myPanel)
}