Consider sort order in UID sort mode of multi-folder search results

program/lib/Roundcube/rcube_imap.php

@@ -988,6 +988,10 @@ class rcube_imap extends rcube_storage
                 $a_msg_headers = array_slice(array_values($a_msg_headers), $from, $slice_length);
             }
             else {
+                if ($this->sort_order != $search_set->get_parameters('ORDER')) {
+                    $search_set->revert();
+                }
+
                 // slice resultset first...
                 $fetch = array();
                 foreach (array_slice($search_set->get(), $from, $slice_length) as $msg_id) {

program/lib/Roundcube/rcube_result_multifolder.php

@@ -130,6 +130,17 @@ class rcube_result_multifolder
     public function revert()
     {
         $this->order = $this->order == 'ASC' ? 'DESC' : 'ASC';
+        $this->index = array();
+
+        // revert order in all sub-sets
+        foreach ($this->sets as $set) {
+            if ($this->order != $set->get_parameters('ORDER')) {
+                $set->revert();
+            }
+            $folder = $set->get_parameters('MAILBOX');
+            $index = array_map(function($uid) use ($folder) { return $uid . '-' . $folder; }, $set->get());
+            $this->index = array_merge($this->index, $index);
+        }
     }