Bug 330467 [Compatibility] Workbench window menu bar submenus keeps growing
Submenus like 'Search > Text' keeps growing in size.
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/MenuManagerRenderer.java
public IContributionItem getContribution(MMenuElement model) {
		return modelToContribution.get(model);
	}
	public MMenuElement getMenuElement(IContributionItem item) {
		return contributionToModel.get(item);
	}
	public void linkModelToContribution(MMenuElement model,
			IContributionItem item) {
		modelToContribution.put(model, item);
		contributionToModel.put(item, model);
	}
	public void clearModelToContribution(MMenuElement model,
			IContributionItem item) {
		modelToContribution.remove(model);
		contributionToModel.remove(item);
	}
	public ContributionRecord getContributionRecord(MMenuElement element) {
		return modelContributionToRecord.get(element);
	}
	/**
	 * @param menuManager
	 * @param menuModel
	 */
	public void reconcileManagerToModel(MenuManager menuManager, MMenu menuModel) {
		List<MMenuElement> modelChildren = menuModel.getChildren();
		HashSet<MOpaqueMenuItem> oldModelItems = new HashSet<MOpaqueMenuItem>();
		HashSet<MOpaqueMenu> oldMenus = new HashSet<MOpaqueMenu>();
		HashSet<MOpaqueMenuSeparator> oldSeps = new HashSet<MOpaqueMenuSeparator>();
		for (MMenuElement itemModel : modelChildren) {
			if (itemModel instanceof MOpaqueMenuSeparator) {