Bug 282900 [CSS] ETabFolder should support setWebbyStyle()
And have field in CSS
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/workbench/ui/renderers/swt/StackModelFactory.java
EList<MPart> kids = element.getParent().getChildren();
		for (Iterator iterator = kids.iterator(); iterator.hasNext();) {
			MPart mPart = (MPart) iterator.next();
			if (mPart == element)
				return index;
			if (mPart.isVisible())
				index++;
		}
		return index;
	}
	@Override
	public void childAdded(final MPart<?> parentElement, MPart<?> element) {
		super.childAdded(parentElement, element);
		if (element instanceof MItemPart<?>) {
			internalChildAdded(parentElement, element);
			
			
			Control ctrl = (Control) element.getWidget();
			if (ctrl != null) {
				showTab((MItemPart<?>) element);
				stylingEngine.style(ctrl);
			}
		}
	}
	private CTabItem findItemForPart(MPart<?> folder, MPart<?> part) {
		CTabFolder ctf = (CTabFolder) folder.getWidget();
		if (ctf == null)
			return null;
		CTabItem[] items = ctf.getItems();
		for (int i = 0; i < items.length; i++) {