Bug 327964 EPartService's hidePart may fail when trying to hide a shared part that's in a shared container
The placeholder retrieval code in the EPartService implementation doesn't go far down deep enough and actually stops at the shared container level. This causes the placeholder of the shared part to not be found.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
}
	public void testShowPart_Id_Unrendered_ACTIVATE2() {
		testShowPart_Id_Unrendered2(PartState.ACTIVATE);
	}
	private void testShowPart_Id_Unrendered3(EPartService.PartState partState) {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		window.setToBeRendered(true);
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPartSashContainer partSashContainer = BasicFactoryImpl.eINSTANCE
				.createPartSashContainer();
		partSashContainer.setToBeRendered(false);
		window.getChildren().add(partSashContainer);
		window.setSelectedElement(partSashContainer);
		MPartStack partStack = BasicFactoryImpl.eINSTANCE.createPartStack();
		partStack.setToBeRendered(false);
		partSashContainer.getChildren().add(partStack);
		partSashContainer.setSelectedElement(partStack);
		MPart part = BasicFactoryImpl.eINSTANCE.createPart();
		part.setElementId("partId");
		part.setToBeRendered(false);
		partStack.getChildren().add(part);
		partStack.setSelectedElement(part);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		MPart shownPart = partService.showPart("partId", partState);