Index: program/include/rcube_message.php
===================================================================
--- program/include/rcube_message.php	(revision 99b8c1e2ac619665c0514b15d8efb5defabb8090)
+++ program/include/rcube_message.php	(revision f12d218831881cd2ffd356e366050d5d97223248)
@@ -613,5 +613,6 @@
                 $line = substr($line, strlen($regs[0]));
 
-                if ($q == $q_level && isset($text[$last])
+                if ($q == $q_level && $line
+                    && isset($text[$last])
                     && $text[$last][strlen($text[$last])-1] == ' '
                 ) {
@@ -632,5 +633,5 @@
                     $line = preg_replace('/^\s/', '', $line);
 
-                    if (isset($text[$last])
+                    if (isset($text[$last]) && $line
                         && $text[$last] != '-- '
                         && $text[$last][strlen($text[$last])-1] == ' '