private function showForm()
 {
     $dataTypeSelect = new DataTypeSelector($this->dataTypeFactory->getTypes(), $this->getLanguage()->getCode());
     $options = array($this->msg('wikibase-listproperties-all')->text() => '');
     $options = array_merge($options, array_flip($dataTypeSelect->getOptionsArray()));
     $formDescriptor = array('datatype' => array('name' => 'datatype', 'type' => 'select', 'id' => 'wb-listproperties-datatype', 'label-message' => 'wikibase-listproperties-datatype', 'options' => $options, 'default' => $this->dataType), 'submit' => array('name' => '', 'type' => 'submit', 'id' => 'wikibase-listproperties-submit', 'default' => $this->msg('wikibase-listproperties-submit')->text()));
     HTMLForm::factory('inline', $formDescriptor, $this->getContext())->setId('wb-listproperties-form')->setMethod('get')->setWrapperLegendMsg('wikibase-listproperties-legend')->suppressDefaultSubmit()->setSubmitCallback(function () {
     })->show();
 }
 /**
  * @see SpecialNewEntity::additionalFormElements()
  */
 protected function additionalFormElements()
 {
     $dataTypeFactory = WikibaseRepo::getDefaultInstance()->getDataTypeFactory();
     $selector = new DataTypeSelector($dataTypeFactory->getTypes(), $this->getLanguage()->getCode());
     $formDescriptor = parent::additionalFormElements();
     $formDescriptor['datatype'] = array('name' => 'datatype', 'type' => 'select', 'options' => array_flip($selector->getOptionsArray()), 'id' => 'wb-newproperty-datatype', 'label-message' => 'wikibase-newproperty-datatype');
     return $formDescriptor;
 }