Participant Role appears to not be available when editing an Event's Schedule Reminder

Steps to replicate:
1. Create an event scheduled reminder but do not restrict recipients to specific role(s)
2. Edit that scheduled reminder.

Issue: The 'recipient' fields are populated with 'limit to' and 'participant role', but there is no list to choose a role from.

You need to change from 'participant role' to another option and then back again to get the list of roles to appear.

There's also some other jScript / DOM problems on this form when it's used for SMS Scheduled Reminders:

• the maxCharInfoDisplay() function in SMSCommon.tpl isn't firing (but it works when that .tpl is included in templates/Contact/Form/Task/SMS.tpl)
• the Update Template / Save As New Template show/hide functionality isn't working properly - both checkboxes are shown even though I haven't selected an existing template.

(You will need to install the Clickatell extension and then Admin > System Settings > SMS Provider > Add in order to test these issues. Related comments here : https://issues.civicrm.org/jira/browse/CRM-13912