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
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());
		assertTrue(part2.isToBeRendered());
		partService1.hidePart(part1);
		assertFalse(part1.isToBeRendered());
		assertTrue(part2.isToBeRendered());
		partService2.hidePart(part2);
		assertFalse(part1.isToBeRendered());
		assertFalse(part2.isToBeRendered());
	}
	private void testHidePart_Tagged(boolean tagged) {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPart part = BasicFactoryImpl.eINSTANCE.createPart();
		window.getChildren().add(part);
		window.setSelectedElement(part);
		if (tagged) {
			part.getTags().add(EPartService.REMOVE_ON_HIDE_TAG);
		}
		initialize(applicationContext, application);
		getEngine().createGui(window);