Bug 321755 EPS adds a part without considering its placeholder if no target container or part stacks could be found
The summary probably makes no sense. Will deliver a fix with a test in a bit.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
window.setSelectedElement(perspectiveStack);
		MPerspective perspective = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();
		perspectiveStack.getChildren().add(perspective);
		perspectiveStack.setSelectedElement(perspective);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();
		perspective.getChildren().add(partA);
		perspective.setSelectedElement(partA);
		MWindow detachedWindow = BasicFactoryImpl.eINSTANCE.createWindow();
		perspective.getWindows().add(detachedWindow);
		MPart partB = BasicFactoryImpl.eINSTANCE.createPart();
		detachedWindow.getChildren().add(partB);
		detachedWindow.setSelectedElement(partB);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = window.getContext().get(EPartService.class);
		partService.activate(partA);
		assertEquals(partA, partService.getActivePart());
		partService.activate(partB);
		assertEquals(partB, partService.getActivePart());
	}
	public void testCreatePart() {
		MApplication application = createApplication(1, new String[1][0]);
		MWindow window = application.getChildren().get(0);
		MPartDescriptor partDescriptor = org.eclipse.e4.ui.model.application.descriptor.basic.impl.BasicFactoryImpl.eINSTANCE
				.createPartDescriptor();
		partDescriptor.setElementId("partId");
		application.getDescriptors().add(partDescriptor);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(