wpForo is not meant to be edited in Colibri Page Builder. I’m not sure about any other page builders. But in my case, it was Colibri.

I wasn’t trying to style the forum, but edit the padding of the forum wrapper in Colibri because there were gaps I wanted to fill, as well as get rid of the hero header. I just wanted the navigation bar and the forum.

When the /community/ directory is edited in CPB, it breaks the “Leave a reply” TinyMCE. I’m not sure how they fixed it or why it breaks the JavaScript, but I’m going to ask them how to fix it if I ever need to edit the page again to add a widget. 

But I did download an advanced editor tool for TinyMCE, and one of the options is greyed out because it says the editor style sheet is missing. I'm guessing anyway. Here's the message.

Disabled: A stylesheet file named editor-style.css was not added by your theme.

your problem is directly connected to the TinyMCE editor JS file. For some reason, the rich editor JS fine is not loaded. It’s disabled. There is an option called "Disable the visual editor when writing" in each user Dashboard > Users > Edit Profile admin page. It seems this option is enabled for all users, or somewhere in your theme the Rich Editor is disabled for front-end use. You should find the plugin which stops loading TinyMCE rich editor on front-end, or you should check all options of your theme to make sure it doesn't have such an option. but the first, you should edit user profile in dashboard and make sure the "Disable the visual editor when writing" option is not enabled.

And some 30.000+ installations use wpForo (according to Wordpress.org), so you understand that this is NOT an issue with wpForo.

What is F12 (your browser console) telling you? Is there any red error during the issue?

(checking Colibri Page Builder Wordpress.org forums, all i see is critical error issues and reports.....)

Still, i don't know.

But this is a conflict with something.