Bug 294493 XMI definition of part icon is ignored
The icon URI definition for parts seem to be ignored as the part tabs don't have any icons.
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/workbench/ui/renderers/swt/SWTPartRenderer.java
public void processContents(MElementContainer<MUIElement> container) {
		Widget parentWidget = (Widget) container.getWidget();
		if (parentWidget == null)
			return;
		
		EList<MUIElement> parts = container.getChildren();
		if (parts != null) {
			for (Iterator<MUIElement> childIter = parts.iterator(); childIter
					.hasNext();) {
				MUIElement childME = childIter.next();
				IPresentationEngine renderer = (IPresentationEngine) context
						.get(IPresentationEngine.class.getName());
				renderer.createGui(childME);
			}
		}
	}
	public void bindWidget(MUIElement me, Object widget) {
		me.setWidget(widget);
		((Widget) widget).setData(OWNING_ME, me);
		me.setFactory(this);
		final IStylingEngine engine = (IStylingEngine) getContext(me).get(
				IStylingEngine.SERVICE_NAME);
		engine.setId(widget, me.getId()); 
	}