Bug 307747 EPartService doesn't render new parts
1. Have a part in a stack, it is the selected part. 2. Show another part in that stack using PartState.CREATE or PartState.VISIBLE. 3. The part should've been rendered. It is not.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
application.getDescriptors().add(descriptor);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		MPart shownPart = partService.showPart("partId", PartState.ACTIVATE);
		assertEquals(part, shownPart);
		assertEquals(stack, part.getParent());
	}
	public void testHidePart_PartInAnotherWindow() {
		MApplication application = createApplication(
				new String[] { "partInWindow1" },
				new String[] { "partInWindow2" });
		MWindow window1 = application.getChildren().get(0);
		MWindow window2 = application.getChildren().get(1);
		getEngine().createGui(window1);
		getEngine().createGui(window2);
		EPartService partService1 = (EPartService) window1.getContext().get(
				EPartService.class.getName());
		EPartService partService2 = (EPartService) window2.getContext().get(
				EPartService.class.getName());
		MPart part1 = partService1.findPart("partInWindow1");
		MPart part2 = partService2.findPart("partInWindow2");
		assertTrue(part1.isToBeRendered());
		assertTrue(part2.isToBeRendered());
		partService1.hidePart(part2);
		assertTrue(part1.isToBeRendered());
		assertTrue(part2.isToBeRendered());
		partService2.hidePart(part1);
		assertTrue(part1.isToBeRendered());