Index: trunk/roundcubemail/program/steps/mail/func.inc
===================================================================
--- trunk/roundcubemail/program/steps/mail/func.inc	(revision 2621)
+++ trunk/roundcubemail/program/steps/mail/func.inc	(revision 2623)
@@ -820,5 +820,12 @@
     $body = Q(join("\n", $a_lines), 'replace', false);
 
-    // ... colorize quoted lines
+    // colorize signature
+    if (($sp = strrpos($body, '-- ')) !== false)
+      if (($sp == 0 || $body[$sp-1] == "\n") && $body[$sp+3] == "\n") {
+	$body = substr($body, 0, max(0, $sp))
+	    .'<span class="sig">'.substr($body, $sp).'</span>';
+      }
+
+    // colorize quoted lines
     $a_lines = preg_split('/\n/', $body);
     foreach ($q_lines as $i => $q)