diff --git a/phpgwapi/inc/class.hooks.inc.php b/phpgwapi/inc/class.hooks.inc.php
index 86244ee219..f88ed0ba63 100644
--- a/phpgwapi/inc/class.hooks.inc.php
+++ b/phpgwapi/inc/class.hooks.inc.php
@@ -201,6 +201,18 @@ class hooks
 		return count($this->locations[$location][$app]);
 	}
 
+	/**
+	 * check which apps implement a given hook
+	 *
+	 * @param string $location location-name
+	 * @return array of apps implementing given hook
+	 */
+	function hook_implemented($location)
+	{
+		//error_log(__METHOD__.__LINE__.array2string($this->locations[$location]));
+		return isset($this->locations[$location]) ? array_keys($this->locations[$location]) : array();
+	}
+
 	/**
 	 * Register and/or de-register an application's hooks
 	 *