Bug 126839 [DataBinding] IObservable refactoring
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/swt/ListUpdatableValue.java
for (int i = 0; i < items.length; i++) {
						if (value.equals(items[i])) {
							index = i;
							break;
						}
					}
					list.select(index); 
				}
			}
		} finally {
			updating = false;
		}
		fireChangeEvent(ChangeEvent.CHANGE, oldValue, value);
	}
	public Object computeValue() {
		Assert.isTrue(attribute.equals(SWTProperties.SELECTION),
				"unexpected attribute" + attribute); 
		int index = list.getSelectionIndex();
		if (index >= 0) {
			return list.getItem(index);
		}
		return null;
	}
	public Class getValueType() {
		Assert.isTrue(attribute.equals(SWTProperties.SELECTION),
				"unexpected attribute" + attribute); 
		return String.class;
	}
}