diff --git a/phpgwapi/inc/common_functions.inc.php b/phpgwapi/inc/common_functions.inc.php
index 61dc5d4593..e72b4b08e1 100755
--- a/phpgwapi/inc/common_functions.inc.php
+++ b/phpgwapi/inc/common_functions.inc.php
@@ -1422,13 +1422,12 @@ function __autoload($class)
 }
 
 /**
- * Fail a little bit more gracefully then an uncought exception
- *
- * Does NOT return
- *
+ * Clasify exception for a headline and log it to error_log, if not running as cli
+ * 
  * @param Exception $e
+ * @param string &$headline
  */
-function egw_exception_handler(Exception $e)
+function _egw_log_exception(Exception $e,&$headline=null)
 {
 	if ($e instanceof egw_exception_no_permission)
 	{
@@ -1446,6 +1445,29 @@ function egw_exception_handler(Exception $e)
 	{
 		$headline = try_lang('An error happened');
 	}
+	// log exception to error log, if not running as cli,
+	// which outputs the error_log to stderr and therefore output it twice to the user
+	if(!isset($_SERVER['HTTP_HOST']) || $GLOBALS['egw_info']['flags']['no_exception_handler'] == 'cli')
+	{
+		error_log($headline.': '.$e->getMessage());
+		foreach(explode("\n",$e->getTraceAsString()) as $line) error_log($line);
+		error_log('# Instance='.$GLOBALS['egw_info']['user']['domain'].', User='.$GLOBALS['egw_info']['user']['account_lid'].', URL='.
+			($_SERVER['HTTPS']?'https://':'http://').$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI']);
+	}
+}
+
+/**
+ * Fail a little bit more gracefully then an uncought exception
+ *
+ * Does NOT return
+ *
+ * @param Exception $e
+ */
+function egw_exception_handler(Exception $e)
+{
+	// logging all exceptions to the error_log (if not cli) and get headline
+	_egw_log_exception($e,$headline);
+	
 	// exception handler for cli (command line interface) clients, no html, no logging
 	if(!isset($_SERVER['HTTP_HOST']) || $GLOBALS['egw_info']['flags']['no_exception_handler'] == 'cli')
 	{
@@ -1456,12 +1478,6 @@ function egw_exception_handler(Exception $e)
 		}
 		exit($e->getCode() ? $e->getCode() : 9999);		// allways give a non-zero exit code
 	}
-	// logging all exceptions to the error_log
-	error_log($headline.': '.$e->getMessage());
-	foreach(explode("\n",$e->getTraceAsString()) as $line) error_log($line);
-	error_log('# Instance='.$GLOBALS['egw_info']['user']['domain'].', User='.$GLOBALS['egw_info']['user']['account_lid'].', URL='.
-		($_SERVER['HTTPS']?'https://':'http://').$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI']);
-
 	// regular GUI exception
 	if (!isset($GLOBALS['egw_info']['flags']['no_exception_handler']))
 	{
@@ -1494,9 +1510,9 @@ function egw_exception_handler(Exception $e)
 		header('HTTP/1.1 401 Unauthorized');
 		header('X-WebDAV-Status: 401 Unauthorized', true);
 	}
-	if (is_object($GLOBALS['egw']) && isset($GLOBALS['egw']->common))
+	if (is_object($GLOBALS['egw']))
 	{
-		$GLOBALS['egw']->common->egw_exit();
+		common::egw_exit();
 	}
 	exit;
 }
diff --git a/xajax.php b/xajax.php
index 09ace44179..6080f02a4c 100644
--- a/xajax.php
+++ b/xajax.php
@@ -33,7 +33,7 @@ function xajax_redirect(&$anon_account)
 }
 
 /**
- * Exception handler for xajax, return the message (and trace) as alert() to the user
+ * Exception handler for xajax, return the message (and trace, if enabled) as alert() to the user
  *
  * Does NOT return!
  *
@@ -41,8 +41,20 @@ function xajax_redirect(&$anon_account)
  */
 function ajax_exception_handler(Exception $e)
 {
+	// logging all exceptions to the error_log
+	if (function_exists('_egw_log_exception'))
+	{
+		_egw_log_exception($e,$message);
+	}
 	$response = new xajaxResponse();
-	$response->addAlert($e->getMessage()."\n\n".$e->getTraceAsString());
+	$message .= ($message ? "\n\n" : '').$e->getMessage();
+	
+	// only show trace (incl. function arguments) if explicitly enabled, eg. on a development system
+	if ($GLOBALS['egw_info']['server']['exception_show_trace'])
+	{
+		$message .= "\n\n".$e->getTraceAsString();
+	}
+	$response->addAlert($message);
 	$response->printOutput();
 
 	if (is_object($GLOBALS['egw']))