public $components = array(
	'Categories.CategoryEdit',
);

public $actsAs = array(
	'Categories.Category',
);

<?php echo $this->element('Categories.edit_form'); ?>

public $components = array(
	'Categories.Categories',
);

<?php echo $this->Category->dropDownToggle(array(
		'empty' => true,
		'displayMenu' => true,
	)); ?>

※displayMenu => false に設定すると<button>及び<ul>タグは出力しない。（<li>タグのみ出力）

if (isset($this->params['named']['category_id'])) {
	$conditions['FaqQuestion.category_id'] = $this->params['named']['category_id'];
}

public $components = array(
	'Categories.Categories',
);

<?php echo $this->Category->select('FaqQuestion.category_id', array('empty' => true)); ?>