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
protected Control getOutermost(Control ctrl) {
		
		
		Composite curComposite = ctrl.getParent();
		Control outerMost = ctrl;
		while (curComposite != null
				&& curComposite.getData(AbstractPartRenderer.OWNING_ME) == null
				&& !(curComposite instanceof Shell)) {
			outerMost = curComposite;
			curComposite = curComposite.getParent();
		}
		return outerMost;
	}
	/*
	 * HACK: Create a wrapper composite with appropriate layout for the purpose
	 * of styling margins. See bug #280632
	 */
	protected Composite createWrapperForStyling(Composite parentWidget,
			IEclipseContext context) {
		Composite layoutHolder = new Composite(parentWidget, SWT.NONE);
		addLayoutForStyling(layoutHolder);
		layoutHolder.setData("org.eclipse.e4.ui.css.swt.marginWrapper", true); 
		final IStylingEngine engine = (IStylingEngine) context
				.get(IStylingEngine.SERVICE_NAME);
		engine.setClassname(layoutHolder, "marginWrapper"); 
		return layoutHolder;
	}
	/*
	 * HACK: Add layout information to the composite for the purpose of styling
	 * margins. See bug #280632