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
private int tag = -1;
		private int hc = -1;
		private String parentId;
		private String position;
		private MCoreExpression vexp;
		public Key(String parentId, String position, List<String> tags, MCoreExpression vexp) {
			this.parentId = parentId;
			this.position = position;
			this.vexp = vexp;
			if (tags.contains("scheme:menu")) { 
				tag = 1;
			} else if (tags.contains("scheme:popup")) { 
				tag = 2;
			} else if (tags.contains("scheme:toolbar")) { 
				tag = 3;
			} else {
				tag = 0;
			}
		}
		int getSchemeTag() {
			return tag;
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see java.lang.Object#equals(java.lang.Object)