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.
tests/org.eclipse.jface.tests.databinding/src/org/eclipse/jface/tests/databinding/swt/SWTObservablesTest.java
}
	public void testObserveItemsOfCombo() throws Exception {
		Combo combo = new Combo(shell, SWT.NONE);
		IObservableList list = SWTObservables.observeItems(combo);
		assertNotNull(list);
		assertTrue(list instanceof ComboObservableList);
	}
	public void testObserveItemsOfCCombo() throws Exception {
		CCombo ccombo = new CCombo(shell, SWT.NONE);
		IObservableList list = SWTObservables.observeItems(ccombo);
		assertNotNull(list);
		assertTrue(list instanceof CComboObservableList);
	}
	public void testObserveItemsOfList() throws Exception {
		List list = new List(shell, SWT.NONE);
		IObservableList observableList = SWTObservables.observeItems(list);
		assertNotNull(observableList);
		assertTrue(observableList instanceof ListObservableList);
	}
	public void testObserveItemsOfUnsupportedControl() throws Exception {
		Table table = new Table(shell, SWT.NONE);
		try {
			SWTObservables.observeItems(table);
			fail("Exception should have been thrown");
		} catch (IllegalArgumentException e) {
		}
	}
	public void testObserveSingleSelectionIndexOfTable() throws Exception {
		Table table = new Table(shell, SWT.NONE);
		ISWTObservableValue value = SWTObservables