CKEditor stops loading on existing content after Drupal update to 10.4

Facing the same issue

Are any CKEditor plugin modules installed on affected sites?

When I disable the BigPipe module, the issue disappears.

I can't reproduce this with the standard profile (ckeditor5 and big_pipe installed).

Can you try the following:

1. See if you can reproduce it on a clean install of Drupal 10.4 with only core.

2. As @cilefen says check if you have any ckeditor plugin modules installed and if so let us know which ones.

The most likely cause of this is 🐛 Logic error in Drupal's lazy load for asset aggregation Active interacting badly with a (usually incorrect) contrib library definition. So a third step would be checking contrib library definitions to see if they specify weight for any files.

Hi,
Thanks for the responses. I don't have time the next few days to check this on a fresh install of 10.4.
What I can say is that for me also if I uninstall the bigpipe module I no longer have this problem and I can again use the editor.

I do not have any extra CKeditor plugins installed on this site

🐛 The attachBehaviors() for document is only called after Big Pipe chunks are processed Fixed
🐛 Logic error in Drupal's lazy load for asset aggregation Active

Big Pipe is attempting to attach behaviors too early, and it’s affecting the Tour module as well.

  // Attach behaviors early, if possible.
  Drupal.attachBehaviors(document);

Having a look at the logic in drupal.init.js file

// Allow other JavaScript libraries to use $.
if (window.jQuery) {
  jQuery.noConflict();
}

// Class indicating that JS is enabled; used for styling purpose.
document.documentElement.className += ' js';

// JavaScript should be made compatible with libraries other than jQuery by
// wrapping it in an anonymous closure.
(function (Drupal, drupalSettings) {
  /**
   * Calls callback when document ready.
   *
   * @param {function} callback
   *   The function to be called on document ready.
   */
  const domReady = (callback) => {
    const listener = () => {
      callback();
      document.removeEventListener('DOMContentLoaded', listener);
    };
    if (document.readyState !== 'loading') {
      setTimeout(callback, 0);
    } else {
      document.addEventListener('DOMContentLoaded', listener);
    }
  };

  // Attach all behaviors.
  domReady(() => {
    Drupal.attachBehaviors(document, drupalSettings);
  });
})(Drupal, window.drupalSettings);

Defines a behavior to be run during attach and detach phases.
Attaches all registered behaviors to a page element.
in the drupal.js file

  Drupal.attachBehaviors = function (context, settings) {
    context = context || document;
    settings = settings || drupalSettings;
    const behaviors = Drupal.behaviors;
    // Execute all of them.
    Object.keys(behaviors || {}).forEach((i) => {
      if (typeof behaviors[i].attach === 'function') {
        // Don't stop the execution of behaviors in case of an error.
        try {
          behaviors[i].attach(context, settings);
        } catch (e) {
          Drupal.throwError(e);
        }
      }
    });
  };

Given that a Drupal 10 site was installed with the minimal profile ( not the standard profile )
And later on the BigPipe and CKEditor5, Tour modules were installed
Then the wight of the BigPipe library will follow it's module wight
And affect the CKEditor 5, Tour, Maybe other modules.

rajab natshah → changed the visibility of the branch 3496329-fix-10-4-x to hidden.

Attached a static drupal-core--2024-12-31--3496329--mr-10753.patch file for the 10.4.x
To be used with the Composer Patches

Possible to get a test case showing the issue.

Faced another issue when added the header: true to the drupal/big_pipe library.
The status message will not show up in the site.

Switched to use a custom domReady in the BigPipe script to let work as Drupal init to Attach behaviors early, if possible without errors

Attached a static drupal-core--2024-12-31--3496329--mr-10753.patch file for the 10.4.x to this point from MR10753.
To be used with the Composer Patches

Attached a static drupal-core--2024-12-31--3496329--mr-10753.patch file for the 10.4.x to this point from MR10753.
To be used with the Composer Patches

Attached a static drupal-core--2025-01-02--3496329-32--mr-10753.patch file for the 10.4.x to this point from MR10753.
To be used with the Composer Patches

It helped me with the problem
https://www.drupal.org/project/collapsible_dnd/issues/3497645 🐛 Stop work after update Drupal 10.4 Active

Drupal 10.4.1. Patch #33 💬 CKEditor stops loading on existing content after Drupal update to 10.4 Active work for me