Index: admin/inc/class.uiasyncservice.inc.php
===================================================================
--- admin/inc/class.uiasyncservice.inc.php	(revision 18539)
+++ admin/inc/class.uiasyncservice.inc.php	(working copy)
@@ -47,7 +47,7 @@
 
 			$async = clone($GLOBALS['phpgw']->asyncservice);	// use an own instance, as we might set debug=True
 
-			$async->debug = !!$_POST['debug'];
+			$async->debug = phpgw::get_var('debug', 'bool', 'POST');
 
 			$units = array
 			(
