Support

I disagree.

All extra buttons are rendered by plugins in the Buttons group (folder: editors-xtd). Like all Joomla plugins have an Access setting. If you have set up your viewing access levels and user groups correctly on your site you can assign an Access (viewing access level) to these plugins which only makes them appear on select user groups. I would simply create a new access level called “Editor Buttons Allowed” which includes the user groups that have Support Staff privilege and also add the standard Joomla user groups Editor, Publisher, Manager, Administrator and Super User.

While Joomla allows us to tell the editor to hide the buttons, this happens for everyone, regardless of their access level. This would mean that they'd be hidden from users with the Support Staff privilege. As a result you wouldn't be able to use Canned Replies, a feature which is implemented as a Joomla editor button plugin itself.