assertEquals(content2, p.getWidget(1));
assertEquals(header0, p.getTabWidget(0));
assertEquals(header2, p.getTabWidget(1));
// Remove a header.
header2.removeFromParent();
assertNull(content2.getParent());
assertNull(header2.getParent());
assertEquals(1, p.getWidgetCount());
assertEquals(content0, p.getWidget(0));
assertEquals(header0, p.getTabWidget(0));