doc improvement.

framework/yii/base/ActionFilter.php

@@ -16,10 +16,13 @@ class ActionFilter extends Behavior
 	/**
 	 * @var array list of action IDs that this filter should apply to. If this property is not set,
 	 * then the filter applies to all actions, unless they are listed in [[except]].
+	 * If an action ID appears in both [[only]] and [[except]], this filter will NOT apply to it.
+	 * @see except
 	 */
 	public $only;
 	/**
 	 * @var array list of action IDs that this filter should not apply to.
+	 * @see only
 	 */
 	public $except = array();