Fix undefined field problem

git-svn-id: https://svn.code.sf.net/p/squirrelmail/code/trunk/squirrelmail@12907 7612ce4b-ef26-0410-bec9-ea0150e637f0

diff --git a/functions/imap_messages.php b/functions/imap_messages.php
index 19ce2d7f006d67dc626e5162d975b18e476d871b..e7df007bbc75981942b0c0d738db1aa713044e55 100755 (executable)
--- a/functions/imap_messages.php
+++ b/functions/imap_messages.php
@@ -231,7 +231,9 @@ function get_squirrel_sort($imap_stream, $sSortField, $reverse = false, $aUid =
 
     // sqimap_get_small_header (see above) returns fields in lower case,
     // but the code below uses all upper case
-    foreach ($msgs as $k => $v) $msgs[$k][strtoupper($sSortField)] = $msgs[$k][strtolower($sSortField)];
+    foreach ($msgs as $k => $v) 
+        if (isset($msgs[$k][strtolower($sSortField)])) 
+            $msgs[$k][strtoupper($sSortField)] = $msgs[$k][strtolower($sSortField)];
 
     $aUid = array();
     $walk = false;