Bug 303305 EPS cannot handle being asked for from the application's context
Right now we have this... @Inject @Named(EPartService.PART_SERVICE_ROOT) private MElementContainer<MUIElement> rootContainer; ...which will be 'null' if the question was posed to the application's context. Right now, I cannot use EPS in the SaveHandler because I get an (effectively) useless EPartService (filled with null fields).
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/workbench/ui/internal/PartServiceImpl.java
* org.eclipse.e4.workbench.modeling.EPartService#deactivate(org.eclipse.e4.ui.model.application
	 * .MPart)
	 */
	public void deactivate(MPart part) {
		MElementContainer<MUIElement> parent = part.getParent();
		MPart oldSelectedElement = (MPart) parent.getSelectedElement();
		if (oldSelectedElement == part) {
			parent.setSelectedElement(null);
			internalFixContext(null, oldSelectedElement);
		}
	}
	private MPartDescriptor findDescriptor(String id) {
		for (MPartDescriptor descriptor : application.getDescriptors()) {
			if (descriptor.getId().equals(id)) {
				return descriptor;
			}
		}
		return null;
	}
	private MPart createPart(MPartDescriptor descriptor) {
		return descriptor == null ? null : (MPart) EcoreUtil.copy((EObject) descriptor);
	}
	public MPart createPart(String id) {
		MPartDescriptor descriptor = findDescriptor(id);
		return createPart(descriptor);
	}
	private MPart addPart(MPart providedPart, MPart localPart) {
		if (providedPart == localPart && isInContainer(providedPart)) {
			return providedPart;
		}