*
* @return A selection builder, or null if no appropriate one can be found
*/
private SelectionBuilder getSelectionBuilder() {
IStructuredSelection selection = (IStructuredSelection) criteriaList.getSelection();
SelectionType type = (SelectionType) selection.getFirstElement();
SelectionBuilder builder = null;
if (SelectionType.DEFAULT == type) {
builder = POLICY_FACTORY.createDefaultSelectionBuilder();
} else if (SelectionType.ENCODING == type) {