Details
Description
Reproduced on a local 3.3 alpha install and also on sandbox (which I think is still 3.2, although things are working in an older 3.2 local install)
e.g.
http://sandbox.civicrm.org/civicrm/admin/messageTemplates/add?action=update&id=7&reset=1 should bring up the contribution receipt template, but it looks like a blank new form.