Steps to recreate:
1. Access a database activity e.g. http://qa.moodle.net/mod/data/view.php?id=18
2. Click on the template tab
3. Click the disable editor button.
As well as the editor being disabled, the template is also saved, and any html table tags are stripped. This is terrible for list views which use a table!
Furthermore, if the editor is disabled and then the template is edited and then saved, the editor becomes automatically enabled again and any html table tags are again stripped.