TinyMCERTE and Sticky Toolbar

I’ve added an external config file to my install of TinyMCE Rich Text Editor which I’ve confirmed is working because I’ve been able to give it other directives that it’s listening to.

Current contents of the file are {"toolbar_sticky":true} per the documentation at User interface options | Docs | TinyMCE

I can see in the HTML that loads in the manager that the toolbar has the class “tox-tinymce–toolbar-sticky-off” has been applied to the editor.

Just wondering if anyone has had any success in getting a sticky toolbar going in the manager and if so, what I might be doing wrong.