Bug 326177 EPartService's getActivePart() does not appear to work properly for an application with multiple windows
Based on the code in PartServiceCreationFunction, the EPartService implementation being returned when an application's context is queried seems to be a window-level EPartService implementation.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
"The part should have been created so it should have a context",
				partA2.getContext());
		assertEquals(
				"This part has not been instantiated yet, it should have no context",
				null, partB2.getContext());
		shownPart = partService.showPart("partB2",
				EPartService.PartState.CREATE);
		assertTrue(partService.isPartVisible(partA1));
		assertTrue(partService.isPartVisible(partB1));
		assertEquals(partA1, partService.getActivePart());
		assertEquals(shownPart, partB2);
		assertNotNull(
				"The part should have been created so it should have a context",
				partA2.getContext());
		assertNotNull(
				"The part should have been created so it should have a context",
				partB2.getContext());
	}
	public void testShowPart_Id_CREATE2() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		MPartDescriptor partDescriptor = org.eclipse.e4.ui.model.application.descriptor.basic.impl.BasicFactoryImpl.eINSTANCE
				.createPartDescriptor();
		partDescriptor.setElementId("partB");
		partDescriptor.setCategory("aCategory");
		application.getDescriptors().add(partDescriptor);
		MPartStack partStack = BasicFactoryImpl.eINSTANCE.createPartStack();
		partStack.setElementId("aCategory");