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
initialize(applicationContext, application);
		
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		partService.hidePart(partB, force);
	}
	public void testHidePart_Bug325148_Unrendered_True() {
		testHidePart_Bug325148_Unrendered(true);
	}
	public void testHidePart_Bug325148_Unrendered_False() {
		testHidePart_Bug325148_Unrendered(false);
	}
	private MApplication createApplication(String partId) {
		return createApplication(new String[] { partId });
	}
	private MApplication createApplication(String... partIds) {
		return createApplication(new String[][] { partIds });
	}
	private MApplication createApplication(String[]... partIds) {
		return createApplication(partIds.length, partIds);
	}
	private MApplication createApplication(int windows, String[][] partIds) {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		for (int i = 0; i < windows; i++) {
			MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
			application.getChildren().add(window);
			MPartStack partStack = BasicFactoryImpl.eINSTANCE.createPartStack();