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.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
part.getMenus().addAll(EcoreUtil.copyAll(descriptor.getMenus()));
		if (descriptor.getToolbar() != null) {
			part.setToolbar((MToolBar) EcoreUtil.copy((EObject) descriptor.getToolbar()));
		}
		part.setCloseable(descriptor.isCloseable());
		part.setContributionURI(descriptor.getContributionURI());
		part.setLabel(descriptor.getLabel());
		part.setIconURI(descriptor.getIconURI());
		part.setTooltip(descriptor.getTooltip());
		part.getHandlers().addAll(EcoreUtil.copyAll(descriptor.getHandlers()));
		part.getTags().addAll(descriptor.getTags());
		part.getBindingContexts().addAll(descriptor.getBindingContexts());
		return part;
	}
	public MPart createPart(String id) {
		MPartDescriptor descriptor = findDescriptor(id);
		return createPart(descriptor);
	}
	public MPlaceholder createSharedPart(String id, MWindow sharedWindow) {
		return createSharedPart(id, sharedWindow, false);
	}
	public MPlaceholder createSharedPart(String id, MWindow sharedWindow, boolean force) {
		
		MPart sharedPart = null;
		
		if (!force) {
			for (MUIElement element : sharedWindow.getSharedElements()) {
				if (element.getElementId().equals(id)) {
					sharedPart = (MPart) element;
					break;