TinyMCE editor doesn't load properly when initializing on Visual Tab (Firefox) [again]

[patkemper]

This issue had been fixed a few years ago. Now with WP 6.7 the issue reappeared.

I'll just copy-paste the original description (thanks to metalandcoffee):
"TinyMCE editors within my custom metaboxes will sometimes fail to load/initialize when using the Firefox browser. This only happens when the editor is initializing on the Visual tab. If I switch to the Text tab and then reload the page, the editor initializing normally."

Original ticket:
https://core.trac.wordpress.org/ticket/52133

Changeset that fixed the issue back in 2021:
https://core.trac.wordpress.org/changeset/51082

[mayanktripathi32]

Hello Patkemper,

I attempted to replicate the issue using a fresh installation of version 6.7. However, everything seems to be functioning as expected. The editor loaded successfully in visual mode without any problems on my end.

I have attached a screencast for the same: ​https://streamable.com/ynxovp

If the issue persists on your side, could you kindly share a video recording of the problem along with the relevant code for the metafield? This will help in diagnosing the issue more effectively.

Best regards,
Mayank

[benediktgrether]

Hi everyone.

Our client manages their website independently and uses SCF (Secure Custom Fields) with WYSIWYG editor fields to input content.

Problem:
When switching between the "Text" and "Visual Editor" tabs, all content disappears, and the text box remains empty (white). This significantly impacts the ability to edit content.

Console Error:
The following error appears in the browser's developer console:

Uncaught TypeError: can't access property "setBaseAndExtent", n is null
tinymce.min.js:2:291933

Here is a Screen Record.
​https://go.screenpal.com/watch/cZXtjXnV7GL

Steps to Reproduce:

Log in to the WordPress admin panel.
Edit an SCF field with a WYSIWYG editor.
Switch between the "Text" and "Visual Editor" tabs.
Notice that the content disappears, leaving an empty text box.
Expected Behavior:
The content in the WYSIWYG field should not disappear when switching between "Text" and "Visual Editor."

Additional Information:

WordPress Version: 6.7.1
SCF Version: 6.3.10.2
Browser and Version: Firefox Developer Edition - Version 134.0b1 (64-Bit) | Firefox Edition - Version 131.0 (64-Bit) (Both are affected).

We kindly request support to analyze and resolve this issue.
Benedikt.