Bug 341273 ESS will not work without parts
While windows without any parts probably isn't a very interesting shape, it is still possible to create such a thing. In this scenario, the ESS may not work properly because we rely solely on the active part for selection information. It should be possible to have a selection at the window level as-is.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/SelectionServiceImpl.java
* org.eclipse.e4.ui.selection.ESelectionService#addSelectionListener(org.eclipse.e4.ui.selection
	 * .ISelectionListener)
	 */
	public void addSelectionListener(ISelectionListener listener) {
		IEclipseContext rootContext = serviceRoot.getContext();
		if (rootContext != context) {
			ESelectionService selectionService = (ESelectionService) rootContext
					.get(ESelectionService.class.getName());
			selectionService.addSelectionListener(listener);
		}
		genericListeners.add(listener);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.selection.ESelectionService#removeSelectionListener(org.eclipse.e4.ui.selection
	 * .ISelectionListener)
	 */
	public void removeSelectionListener(ISelectionListener listener) {
		
		if (context != null) {
			IEclipseContext rootContext = serviceRoot.getContext();
			if (rootContext != context) {
				ESelectionService selectionService = (ESelectionService) rootContext
						.get(ESelectionService.class.getName());
				selectionService.removeSelectionListener(listener);
			}
			genericListeners.remove(listener);
		}