Bug 238909 [DataBinding] Correctly set the staleness state of the validation status observable of the MultiValidator
For Bindings, the validation status observable should be stale whenever either the target or model observable is stale. For the MultiValidator, the validation status observable should be stale whenever any of its dependencies accessed from within the MultiValidator#validate() is stale.
bundles/org.eclipse.core.databinding/src/org/eclipse/core/databinding/validation/MultiValidator.java
private Realm realm;
	private IObservableValue validationStatus;
	private IObservableValue unmodifiableValidationStatus;
	private WritableList targets;
	private IObservableList unmodifiableTargets;
	private IObservableList models;
	IListChangeListener targetsListener = new IListChangeListener() {
		public void handleListChange(ListChangeEvent event) {
			event.diff.accept(new ListDiffVisitor() {
				public void handleAdd(int index, Object element) {
					((IObservable) element)
							.addChangeListener(dependencyListener);
				}
				public void handleRemove(int index, Object element) {
					((IObservable) element)
							.removeChangeListener(dependencyListener);
				}