Adding a button to the TinyMCE toolbar in the Divi Visual Builder

[JeePeeNL]

Problem Description

I created a custom plugin to add a 'Formats' dropdown to the TinyMCE toolbar, based on the code provided at WPbeginner (method2) https://www.wpbeginner.com/wp-tutorials/how-to-add-custom-styles-to-wordpress-visual-editor/

The button is added to the toolbar in the classic WP editor and to the Divi text module when you open the text module from the Backend builder. However, it's not there when you open the text module in the Visual Builder.

What needs to be changed to add the button to the Tiny toolbar so it is compatible with the Divi Visual Builder?

Thanks
JP

Steps To Reproduce

1. Download the attached plugin file and remove the .txt extension
   TinyMCE-custom-styles.php.txt
2. Install the plugin file and activate
3. In Divi » them options » builder » advanced, enable the classic editor
4. Start a post with the classic editor and note that the 'Formats' dropdown is available
5. Click to use the Divi builder (backend), add a section, row and text module and note that the 'Formats' dropdown is available
6. Save the post, switch to the Visual Builder and note that the 'Formats' dropdown is NOT available

Screencapture video: https://somup.com/cZiIoMENke