diff --git a/program/js/list.js b/program/js/list.js
index 560ee0d9b..04aec1c99 100644
--- a/program/js/list.js
+++ b/program/js/list.js
@@ -313,7 +313,7 @@ insert_row: function(row, before)
     if (row.id) domrow.id = row.id;
     if (row.className) domrow.className = row.className;
     if (row.style) $.extend(domrow.style, row.style);
-    if (row.uid) $(domrow).data('uid', row.uid);
+    if (row.uid) $(domrow).data('uid', String(row.uid)); // #1489906
 
     for (var e, domcell, col, i=0; row.cols && i < row.cols.length; i++) {
       col = row.cols[i];
diff --git a/program/lib/Roundcube/rcube_imap.php b/program/lib/Roundcube/rcube_imap.php
index 4b32c466b..bf588cacf 100644
--- a/program/lib/Roundcube/rcube_imap.php
+++ b/program/lib/Roundcube/rcube_imap.php
@@ -1691,12 +1691,15 @@ class rcube_imap extends rcube_storage
                 $string_offset = $m[1] + strlen($m[0]) + 4; // {}\r\n
                 $string = substr($str, $string_offset - 1, $m[0]);
                 $string = rcube_charset::convert($string, $charset, $dest_charset);
-                if ($string === false) {
+
+                if ($string === false || !strlen($string)) {
                     continue;
                 }
+
                 $res .= substr($str, $last, $m[1] - $last - 1) . rcube_imap_generic::escape($string);
                 $last = $m[0] + $string_offset - 1;
             }
+
             if ($last < strlen($str)) {
                 $res .= substr($str, $last, strlen($str)-$last);
             }