Bug 123758 [DataBinding] CComboUpdatableValue Doesn't Handle Text That Isn't in The List of Selected Items
The current implementation of CComboUpdatableValue will only allow setting text if the value is in the list of possible selection values. In reality the CCombo allows either a manually entered value (which may not be in the list) or the selection of a value from the drop down list. I'll be submitting a patch for this shortly.
tests/org.eclipse.jface.tests.databinding/src/org/eclipse/jface/tests/databinding/scenarios/ReadOnlyComboScenarios.java
return ((Lodging) element).getName();
		}
	};
	ILabelProvider accountLabelProvider = new LabelProvider() {
		public String getText(Object element) {
			return ((Account) element).getCountry();
		}
	};
	protected void setUp() throws Exception {
		super.setUp();
		getComposite().setLayout(new FillLayout());
		combo = new Combo(getComposite(), SWT.READ_ONLY | SWT.DROP_DOWN);
		cviewer = new ComboViewer(combo);
		catalog = SampleData.CATALOG_2005; 
	}
	protected void tearDown() throws Exception {
		combo.dispose();
		combo = null;
		cviewer = null;
		super.tearDown();
	}
	protected Object getViewerSelection() {
		return ((IStructuredSelection) cviewer.getSelection())
				.getFirstElement();
	}
	/**
	 * @return the ComboViewer's domain object list
	 */
	protected List getViewerContent(ComboViewer cviewer) {
		Object[] elements = ((IStructuredContentProvider) cviewer