Bug 81070 ElementMapper should not use Integer keys computed from System#identityHashCode
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/workingsets/WorkingSetModel.java
toAdd.remove(oldElements[i]);
			}
			for (int i= 0; i < newElements.length; i++) {
				toRemove.remove(newElements[i]);
			}
			
		}
		public IWorkingSet getFirstWorkingSet(Object element) {
			return (IWorkingSet)getFirstElement(fElementToWorkingSet, element);
		}
		public List getAllWorkingSets(Object element) {
			return getAllElements(fElementToWorkingSet, element);
		}
		public IWorkingSet getFirstWorkingSetForResource(IResource resource) {
			return (IWorkingSet)getFirstElement(fResourceToWorkingSet, resource);
		}
		public List getAllWorkingSetsForResource(IResource resource) {
			return getAllElements(fResourceToWorkingSet, resource);
		}
		private void put(IWorkingSet ws) {
			Integer workingSetKey= new Integer(System.identityHashCode(ws));
			if (fWorkingSetToElement.containsKey(workingSetKey))
				return;
			IAdaptable[] elements= ws.getElements();
			fWorkingSetToElement.put(workingSetKey, elements);
			for (int i= 0; i < elements.length; i++) {
				addElement(elements[i], ws);
			}
		}
		private void addElement(IAdaptable element, IWorkingSet ws) {