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 text attribute of the provided
	 * <code>control</code>. The supported types are:
	 * <ul>
	 * <li>org.eclipse.swt.widgets.Label</li>
	 * <li>org.eclipse.swt.custom.Label</li>
	 * <li>org.eclipse.swt.widgets.Combo</li>
	 * <li>org.eclipse.swt.custom.CCombo</li>
	 * </ul>
	 * 
	 * @param control
	 * @return observable value
	 * @throws IllegalArgumentException
	 *             if <code>control</code> type is unsupported
	 */
	public static ISWTObservableValue observeText(Control control) {
		if (control instanceof Label) {
			return new LabelObservableValue((Label) control);
		} else if (control instanceof CLabel) {
			return new CLabelObservableValue((CLabel) control);
		} else if (control instanceof Combo) {
			return new ComboObservableValue((Combo) control, SWTProperties.TEXT);
		} else if (control instanceof CCombo) {
			return new CComboObservableValue((CCombo) control,
					SWTProperties.TEXT);
		}
		throw new IllegalArgumentException(
				"Widget [" + control.getClass().getName() + "] is not supported."); 
	}
	/**