Validate handler for views_ui_edit_display_form
function views_ui_edit_display_form_validate($form, &$form_state) {
$form_state['view']
->get('executable')->displayHandlers[$form_state['display_id']]
->validateOptionsForm($form['options'], $form_state);
if (form_get_errors()) {
$form_state['rerender'] = TRUE;
}
}