Don't wrap quoted lines at all

program/include/rcube_shared.inc

@@ -259,7 +259,12 @@ function rc_wordwrap($string, $width=75, $break="\n", $cut=false)
   $para = explode($break, $string);
   $string = '';
   while (count($para)) {
-    $list = explode(' ', array_shift($para));
+    $line = array_shift($para);
+    if ($line[0] == '>') {
+      $string .= $line.$break;
+      continue;
+    }
+    $list = explode(' ', $line);
     $len = 0;
     while (count($list)) {
       $line = array_shift($list);