Bug 205248 [Databinding] Observables on Text with FOCUS_OUT event incorrectly notify with no change
If you get an observable on a Text for the FOCUS_OUT event, the model is updated every time, even if there is no change in the value. The observable should not trigger a model change if the Text value is the same as the model value.
bundles/org.eclipse.core.databinding.observable/src/org/eclipse/core/databinding/observable/value/AbstractVetoableValue.java
implements IVetoableValue {
	/**
	 * Creates a new vetoable value.
	 */
	public AbstractVetoableValue() {
		this(Realm.getDefault());
	}
	/**
	 * @param realm
	 */
	public AbstractVetoableValue(Realm realm) {
		super(realm);
	}
	final protected void doSetValue(Object value) {
		Object currentValue = doGetValue();
		ValueDiff diff = Diffs.createValueDiff(currentValue, value);
		boolean okToProceed = fireValueChanging(diff);
		if (!okToProceed) {
			throw new ChangeVetoException("Change not permitted"); 
		}
		doSetApprovedValue(value);
		fireValueChange(diff);
	}
	/**
	 * Sets the value. Invoked after performing veto checks.