code: public void unmaximiseComponent() {
          if (maximisedComponent == null) {
              return;
          }
  
          container.remove(maximisedComponent);
          container.add(containerChild);
          parentMaximisedComponent.add(maximisedComponent);
          container.validate();
  
          containerChild = null;
          parentMaximisedComponent = null;
          maximisedComponent = null;
      }
docs: Unmaximises the current maximised component.
  <p>
  It does nothing if no component is maximised.
  
  @see #maximiseComponent(Component)