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
public static ISWTObservableValue observeMax(Control control) {
		if (control instanceof Spinner) {
			return new SpinnerObservableValue((Spinner) control,
					SWTProperties.MAX);
		} else if (control instanceof Scale) {
			return new ScaleObservableValue((Scale) control, SWTProperties.MAX);
		}
		throw new IllegalArgumentException(
				"Widget [" + control.getClass().getName() + "] is not supported."); 
	}
	/**
	 * Returns an observable observing the text attribute of the provided
	 * <code>control</code>. The supported types are:
	 * <ul>
	 * <li>org.eclipse.swt.widgets.Text</li>
	 * </ul>
	 * 
	 * @param control
	 * @param event event type to register for change events
	 * @return observable value
	 * @throws IllegalArgumentException
	 *             if <code>control</code> type is unsupported
	 */
	public static ISWTObservableValue observeText(Control control, int event) {
		if (control instanceof Text) {
			return new TextObservableValue((Text) control, event);
		}
		throw new IllegalArgumentException(
				"Widget [" + control.getClass().getName() + "] is not supported."); 
	}