Existing data not loaded when multiple CKEditor instances active

Should we fix in the D9+CKEditor 4 integration? Or, should we wait until we try to upgrade to CKEditor 5, which is required in Drupal 10?

Given the EoL for Drupal 9 isn't until November 2023, and we're not sure yet how quickly sites will be migrating to CKEditor 5 and D10, I lean toward fixing this in the existing configuration using Drupal 9 and CKEditor 4.

From what I can tell this is also an issue with any pattern containing the CKEditor WYSIWYG. If any other field that are below the field containing the CKEditor does not get loaded back in because of the it is trying to set readOnly on this instance

setReadOnly: function( isReadOnly ) {
      isReadOnly = ( isReadOnly == null ) || isReadOnly;

      if ( this.readOnly != isReadOnly ) {
        this.readOnly = isReadOnly;

        // Block or release BACKSPACE key according to current read-only
        // state to prevent browser's history navigation (https://dev.ckeditor.com/ticket/9761).
        this.keystrokeHandler.blockedKeystrokes[ 8 ] = +isReadOnly;

        this.editable().setReadOnly( isReadOnly );

        // Fire the readOnly event so the editor features can update
        // their state accordingly.
        this.fire( 'readOnly' );
      }
    },

But this this.editable() is undefined. We can bypass that check using this.readOnly to false so that it doesn't get in the if statement since at this point the editor isn't even full render yet.

I've attached a patch that does allow to get around this and get the CKEditor working with 1 or multiple WYSIWYG field.

Found another bug, when triggering the properties button to hide and show the fields, the CkEditor stays in read only mode. Here is a follow up patch to fix that issue.

Ran into an issue where when the WYSIWYG editor is hidden by properties, it throws an error

TypeError: Cannot read property 'unselectable' of null

I've tried using the delay creation method with both the following delayIfDetached: true and delayIfDetached_callback approach, but was getting editor-delayed-creation-success spam in the console log.

Ended up just using setTimeout to delaying the instance editor from loading until all the properties have finished being set and for the ones that got removed before CKeditor has created an instance for it, were temporary store in global until enabled.

fixed spacing in patch #5

Merged for inclusion in the beta 6 release.