Conflict with HTML Editor Syntax Highlighter plugin

I really like this plugin, but unfortunately it causes a conflict with another plugin I would like to use, HTML Editor Syntax Highlighter.

I use your plugin on the HTML tab to add buttons like <h2>, paragraph tags, etc. But for some reason when I install HTML Editor Syntax Highlighter, all of the custom buttons stop working.

I wonder if you could please help.

Thanks,
Peter

P.S. – I posted a request for help from the other plugin’s developer, too.

https://wordpress.org/plugins/visual-editor-custom-buttons/