Bug 318713 Duplicate toolbar items (navigate group)
SDK 4.0 - I20100701-1105. 1. start fresh workspace ==> navigate group appears twice which is quite confusing and wastes space.
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/TrimBarRenderer.java
super.hideChild(parentElement, child);
		Widget widget = (Widget) child.getWidget();
		if (widget != null) {
			widget.dispose();
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.renderers.swt.SWTPartFactory#processContents
	 * (org.eclipse.e4.ui.model.application.MPart)
	 */
	@Override
	public void processContents(MElementContainer<MUIElement> me) {
		if (!(((MUIElement) me) instanceof MTrimBar))
			return;
		super.processContents(me);
		IEclipseContext ctx = getContext(me);
		ExpressionContext eContext = new ExpressionContext(ctx);
		MElementContainer<?> trimObj = me;
		MTrimBar trimModel = (MTrimBar) trimObj;
		ArrayList<MTrimContribution> toContribute = new ArrayList<MTrimContribution>();
		ContributionsAnalyzer.gatherTrimContributions(trimModel,
				application.getTrimContributions(), trimModel.getElementId(),
				toContribute, eContext);
		addTrimContributions(trimModel, toContribute, ctx, eContext);
	}
	private void addTrimContributions(final MTrimBar trimModel,
			ArrayList<MTrimContribution> toContribute, IEclipseContext ctx,