       out = butler.scheduleJson request.parameter
     when 'setup'
       status = butler.scheduleSetup request.parameter
-      out = ContentService.createTextOutput i18n.get 'setupComplete'
-      out.append "\n"
+      out = HtmlService.createHtmlOutput i18n.get 'setupComplete'
+      out.append "<br />"
       if status is true
         out.append i18n.get 'scheduleSuccessCloseWindow'
       else


    if not messageId or not (message = GmailApp.getMessageById messageId)
      Logger.log "Given message ID '%s' is not valid", messageId
      throw ErrorCodes.INVALID_MESSAGE_ID

    now = new Date().getTime()
    matches = form.when?.match /^(delta|specified):([0-9]+)/

      butSomethingWentWrong:      'But something went wrong: $status$'

      # The following keys must not be changed - they are "error" + ErrorCodes.KEY
      errorMessageIdInvalid:      """Given message ID is not valid. Click <a href="https://mail.google.com/mail?account_id=$email$&message_id=$messageId$&view=conv&extsrc=atom">here</a> to open the according email."""
      errorNoScheduleTime:        'No scheduling time given'
      errorInvalidScheduleTime:   "Given scheduling time '$time$' is not valid"
      errorNoActionSpecified:     'No action (star, marking unread, move to inbox, etc.) specified'
      errorStoringFailed:         'Storing the scheduling action failed'

