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
public void testShowPart_Id_MultipleExists_TrueVISIBLE() {
		testShowPart_Id_MultipleExists(true, PartState.VISIBLE);
	}
	public void testShowPart_Id_MultipleExists_FalseVISIBLE() {
		testShowPart_Id_MultipleExists(false, PartState.VISIBLE);
	}
	public void testShowPart_Id_MultipleExists_TrueCREATE() {
		testShowPart_Id_MultipleExists(true, PartState.CREATE);
	}
	public void testShowPart_Id_MultipleExists_FalseCREATE() {
		testShowPart_Id_MultipleExists(false, PartState.CREATE);
	}
	public void testShowPart_Id_PartInInactivePerspective() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPerspectiveStack perspectiveStack = AdvancedFactoryImpl.eINSTANCE
				.createPerspectiveStack();
		window.getChildren().add(perspectiveStack);
		window.setSelectedElement(perspectiveStack);
		MPerspective perspectiveA = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();
		perspectiveStack.getChildren().add(perspectiveA);
		perspectiveStack.setSelectedElement(perspectiveA);
		MPerspective perspectiveB = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();
		perspectiveStack.getChildren().add(perspectiveB);
		MPartDescriptor partDescriptor = org.eclipse.e4.ui.model.application.descriptor.basic.impl.BasicFactoryImpl.eINSTANCE