Verify that concat_hook_function actually returned something before writing over...

git-svn-id: https://svn.code.sf.net/p/squirrelmail/code/trunk/squirrelmail@6658 7612ce4b-ef26-0410-bec9-ea0150e637f0

diff --git a/functions/display_messages.php b/functions/display_messages.php
index 13bed86966b7b771aad178a3ce6703b6caef6d4d..8b062421e9b9d80c945d0fb68a83b9a383ab43d5 100644 (file)
--- a/functions/display_messages.php
+++ b/functions/display_messages.php
@@ -126,7 +126,10 @@ function error_box($string, $color) {
 
     $err = _("ERROR");
 
-    $string = concat_hook_function('error_box', $string);
+    $ret = concat_hook_function('error_box', $string);
+    if($ret != '') {
+        $string = $ret;
+    }
 
     /* check if the page header has been sent; if not, send it! */
     if(!isset($pageheader_sent) && !$pageheader_sent) {