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
testHidePart_Bug325148(false);
	}
	private void testHidePart_Bug325148_Unrendered(boolean force) {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MPartDescriptor partDescriptor = org.eclipse.e4.ui.model.application.descriptor.basic.impl.BasicFactoryImpl.eINSTANCE
				.createPartDescriptor();
		partDescriptor.setElementId("partId");
		partDescriptor.setCategory("category");
		application.getDescriptors().add(partDescriptor);
		final MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		
		MPartStack stack = BasicFactoryImpl.eINSTANCE.createPartStack();
		stack.setElementId("category");
		window.getChildren().add(stack);
		window.setSelectedElement(stack);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();
		stack.getChildren().add(partA);
		stack.setSelectedElement(partA);
		MPart partB = BasicFactoryImpl.eINSTANCE.createPart();
		partB.setToBeRendered(false);
		stack.getChildren().add(partB);
		
		initialize(applicationContext, application);
		
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());