Fix threaded list sorting on PHP < 5.2.9 (#1488748)

2 files changed, 7 insertions, 4 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 057d2f599..b3aef606c 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,7 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Fix threaded list sorting on PHP < 5.2.9 (#1488748)
 - Plugin API: Add 'email_list' argument for identities data in user_create hook
 - Integrated zipdownload plugin to download all attachments (#1445509)
 - Fix HTML special characters handling in message list/header display (#1488523)
diff --git a/program/include/rcube_result_thread.php b/program/include/rcube_result_thread.php
index 09fa46522..b2325a499 100644
--- a/program/include/rcube_result_thread.php
+++ b/program/include/rcube_result_thread.php
@@ -475,16 +475,18 @@ class rcube_result_thread
             $items = explode(self::SEPARATOR_ITEM, $elem);
             $root  = (int) array_shift($items);
 
-            $result[$elem] = $elem;
-            foreach ($items as $item) {
-                list($lv, $id) = explode(self::SEPARATOR_LEVEL, $item);
+            if ($root) {
+                $result[$root] = $root;
+                foreach ($items as $item) {
+                    list($lv, $id) = explode(self::SEPARATOR_LEVEL, $item);
                     $result[$id] = $root;
+                }
             }
         }
 
         // get only unique roots
         $result = array_filter($result); // make sure there are no nulls
-        $result = array_unique($result, SORT_NUMERIC);
+        $result = array_unique($result);
 
         // Re-sort raw data
         $result = array_fill_keys($result, null);