That sounds possibly like there are some optional settings the plugin wants that you have not set yet?

I've tried a few things but nothing has changed the behavior.  It seems like it is related to the tinyMCE plugin.  I posted a question on the support forum for the plugin and am awaiting a response.  It is probably something simple, but nothing I've tried thus far has resolved it.  For the time being, I've disabled the plugin.

its entirely possible the plugin author thought tinymce would only be used in the admin and used an admin hook for loading it...  but the WordPress API fully supports using the tinymce editor on the front end...  if this is the case, it would be a simple task to change the hook it uses... 

but, of course, could be more complex... 😉

There is an option in the plugin to "only load scripts on gallery pages", however that does not appear to work correctly, as the script that throws the error is in the gallery directory - it does NOT load on the forum display page, but IS loading on the topic and thread display pages.  I don't know enough about the internals of how the Wordpress loading works, plus I know very little about PHP itself.

Still waiting on a response from the author on the issue.

that would be odd... as all those forum pages you mention are the same wp page...  as far as most plugins would know, its just that one page...  might mean something else is doing the loading...  

are you displaying galleries in forum posts?

are you using any shortcodes in forum posts?  you  might try going to forum - options - content settings and disable shortcodes - or just allow the ones you want... 

longshot really... still need to figure out why that plugin is throwing the js errors...

No galleries in the forum.  I use it on one page to display some historical photos.

I checked for a shortcodes option in the forum option content settings and the only thing I could find was the "filter shortcodes" option (which is checked, and there is nothing in the allowed box) - if I'm understanding this option correctly, it should disable shortcodes in forum posts.

It is an odd issue - and I'm still waiting on a response.  At this point I'm almost ready to migrate to a different method for the photos - as I said, I really only use it on one page and I know Wordpress has changed how it works with images - I may just opt to use that instead if it works well.

Thanks for the other ideas.

We like and applaud plugins that do not load everything on all page requests but allow the user to specify where they are to be used so code is only loaded where needed. Sadly - so few seem to do this very simple thing.

some folks have had good success using a plugin like the Plugin Organizer (https://wordpress.org/plugins/.....organizer/) which allows you to only load plugins on specific pages or other methods...

Thank you for the suggestion on the plugin organizer.  It took me a bit to figure out how it worked - I had actually installed it before but it appeared to be rather difficult to configure, but after I spent a few minutes it is really pretty easy.  I suppressed the gallery from the forum page and both seem to be working fine now.  Since I still have not heard anything back from the plugin author, I think this will be my "fix".

Thanks again for the superb support.

good news!  glad everything working out now!