/**
  * show mail
  */
 protected function showMail()
 {
     global $lng, $ilCtrl;
     include_once "./Services/Mail/classes/class.ilPDMailGUI.php";
     $mail_gui = new ilPDMailGUI();
     include_once "./Services/PersonalDesktop/classes/class.ilPDContentBlockGUI.php";
     $content_block = new ilPDContentBlockGUI();
     $content_block->setContent($mail_gui->getPDMailHTML($_GET["mail_id"], $_GET["mobj_id"]));
     $content_block->setTitle($lng->txt("message"));
     $content_block->setColSpan(2);
     $content_block->setImage(ilUtil::getImagePath("icon_mail.png"));
     $content_block->addHeaderCommand($ilCtrl->getLinkTargetByClass("ilpersonaldesktopgui", "show"), $lng->txt("selected_items_back"));
     if ($_GET["mail_mode"] != "system") {
         $content_block->addBlockCommand("ilias.php?baseClass=ilMailGUI&mail_id=" . $_GET["mail_id"] . "&mobj_id=" . $_GET["mobj_id"] . "&type=reply", $lng->txt("reply"));
         $content_block->addBlockCommand("ilias.php?baseClass=ilMailGUI&mail_id=" . $_GET["mail_id"] . "&mobj_id=" . $_GET["mobj_id"] . "&type=read", $lng->txt("inbox"));
         $ilCtrl->setParameter($this, 'mail_id', (int) $_GET['mail_id']);
         $content_block->addBlockCommand($ilCtrl->getLinkTarget($this, 'deleteMail'), $lng->txt('delete'));
     } else {
         $ilCtrl->setParameter($this, "mail_id", $_GET["mail_id"]);
         $ilCtrl->setParameter($this, "mobj_id", $_GET["mobj_id"]);
         $content_block->addBlockCommand($ilCtrl->getLinkTarget($this, "deleteMail"), $lng->txt("delete"));
         $ilCtrl->clearParameters($this);
     }
     return $content_block->getHTML();
 }