Bug 327765 EPartService will hide a part of another perspective
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
application.setSelectedElement(window);
		MPartStack stackA = BasicFactoryImpl.eINSTANCE.createPartStack();
		window.getChildren().add(stackA);
		window.setSelectedElement(stackA);
		MPartStack stackB = BasicFactoryImpl.eINSTANCE.createPartStack();
		window.getChildren().add(stackB);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();
		stackA.getChildren().add(partA);
		stackA.setSelectedElement(partA);
		MPart partB = BasicFactoryImpl.eINSTANCE.createPart();
		stackB.getChildren().add(partB);
		stackB.setSelectedElement(partB);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = window.getContext().get(EPartService.class);
		partService.hidePart(partA);
		assertEquals(partB, partService.getActivePart());
	}
	public void testHidePart_ActivationHistory04() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPartStack stack = BasicFactoryImpl.eINSTANCE.createPartStack();
		window.getChildren().add(stack);
		window.setSelectedElement(stack);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();
		stack.getChildren().add(partA);
		stack.setSelectedElement(partA);