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/src/org/eclipse/e4/ui/internal/workbench/ContributionsAnalyzer.java
if (Util.equals(me.getElementId(), element.getElementId())
					&& element.getClass().isInstance(me)
					&& (element instanceof MMenuSeparator || element instanceof MMenu)) {
				return true;
			}
		}
		return false;
	}
	private static boolean containsMatching(List<MToolBarElement> children, MToolBarElement me) {
		for (MToolBarElement element : children) {
			if (Util.equals(me.getElementId(), element.getElementId())
					&& element.getClass().isInstance(me)
					&& (element instanceof MToolBarSeparator || element instanceof MToolBar)) {
				return true;
			}
		}
		return false;
	}
	private static boolean containsMatching(List<MTrimElement> children, MTrimElement me) {
		for (MTrimElement element : children) {
			if (Util.equals(me.getElementId(), element.getElementId())
					&& element.getClass().isInstance(me)
					&& (element instanceof MToolBarSeparator || element instanceof MToolBar)) {
				return true;
			}
		}
		return false;
	}
	public static int indexForId(MElementContainer<MMenuElement> parentMenu, String id) {
		if (id == null || id.length() == 0) {