// get PageNavigation by navigation id
PageNavigation navigation = uicomp.getNavigationById(navId);
// open a add navigation popup
UIPopupWindow popUp = uicomp.getChild(UIPopupWindow.class);
UIPageNavigationForm pageNavigation = popUp.createUIComponent(UIPageNavigationForm.class, null, null, popUp);
pageNavigation.setOwnerId(navigation.getOwnerId());
pageNavigation.setOwnerType(navigation.getOwnerType());
pageNavigation.setPriority(String.valueOf(navigation.getPriority()));
pageNavigation.addFormInput();
pageNavigation.setPageNav(navigation);