Bug 137442 [DataBinding] (C)ComboObservableValue should bind to selection index
3.2M6: I propose to extend (C)ComboObservableValue such that they could bind int.class values for pure selection changes of an otherwise immutable combo content. E.g. swtbinding allows such binding to an index holder and the class would attach as SelectionListener where it asks the combo for its selection index. Maybe the corresponding property should be assigned to SWTProperties.SELECTION_INDEX. Similar arguments could be given for corresponding extensions for SWT-List widgets.
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/swt/SWTObservables.java
* Returns an observable observing the items attribute of the provided
	 * <code>control</code>. The supported types are:
	 * <ul>
	 * <li>org.eclipse.swt.widgets.Combo</li>
	 * <li>org.eclipse.swt.custom.CCombo</li>
	 * <li>org.eclipse.swt.widgets.List</li>
	 * </ul>
	 * 
	 * @param control
	 * @return observable list
	 * @throws IllegalArgumentException
	 *             if <code>control</code> type is unsupported
	 */
	public static IObservableList observeItems(Control control) {
		if (control instanceof Combo) {
			return new ComboObservableList((Combo) control);
		} else if (control instanceof CCombo) {
			return new CComboObservableList((CCombo) control);
		} else if (control instanceof List) {
			return new ListObservableList((List) control);
		}
		throw new IllegalArgumentException(
				"Widget [" + control.getClass().getName() + "] is not supported."); 
	}
	/**
	 * Returns an observable observing the single selection index attribute of
	 * the provided <code>control</code>. The supported types are:
	 * <ul>
	 * <li>org.eclipse.swt.widgets.Table</li>
	 * </ul>