It is not possible to have the embedded content modal open another modal.

So I'm actually still seeing this problem. So I have a custom plugin that adds a custom callout into the editor. This plugin contains a media field, so I have added a media field to the embedded content modal. Here is what the code looks like:

$form['image'] = $this->getEntityBrowserForm(
  // Entity Browser config entity ID.
  'entity_browser_id_here',
  // Default value as a string.
  $image ?? '',
  // Cardinality.
  1,
  // The view mode to use when displaying the entity in the table.
  'preview'
);
// Convert the wrapping container to a details element.
$form['image']['#type'] = 'details';
$form['image']['#title'] = $this->t('Image');
$form['image']['#open'] = TRUE;

This was based on the example from here.

This works fine using ckeditor4...I can make a selection and it gets inserted right into ckeditor (the media ID is stored as an html attribute like this: <callout data-image="media:1"></callout>. However in ckeditor5, when I go to submit the embedded content form, nothing happens. No errors in the console either. My media field is optional, so if I don't click the 'select media' button, everything is fine. The html gets inserted into the editor correctly and the data-image attribute is just blank. However, if I click 'select media' to open up the modal, then it breaks. Even if I immediately close the modal without making a selection, it still breaks. No HTML gets inserted into the editor.

I tried the patches listed above, but no luck.

@nuez, any possible idea what could be happening here? I see on the module home page it says "Drupal cannot deal with multiple modals. This will become an issue if you use this text filter in a modal, or you open a modal from the Embedded Content plugin form (Say for selecting a media entity with the Media Browser)". I'm just wondering if you ever saw this working using the media browser?

I am using https://www.drupal.org/project/uswds_ckeditor_integration with the embed content. But when I click on the embed content icon, its showing the loading icon for a second but doesn't load the modal window with the dropdown. When I debugged I am seeing AJAX error as below,
nAn AJAX HTTP error occurred.\nHTTP Result Code: 200\nDebugging information follows.\nPath: /embedded-content/dialog\nStatusText: OK\nResponseText: Deprecated: strlen(): Passing null to parameter #1 ($string) of type string is deprecated in /app/web/core/lib/Drupal/Component/Utility/Unicode.php on line 477\nDeprecated: str_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in /app/web/core/lib/Drupal/Component/Utility/Xss.php on line 69\n

It looks like the patch from #3 no longer applies:

$ patch -p1 < allow-stacked-modals.patch 
patching file src/Form/EmbeddedContentDialogForm.php
Hunk #1 FAILED at 80.
Hunk #2 succeeded at 189 (offset -4 lines).
1 out of 2 hunks FAILED -- saving rejects to file src/Form/EmbeddedContentDialogForm.php.rej

It looks like there should be a note on the project page, that nested modals issue currently can't be solved.

Reroll for those using patches, also pushed updated MR

With the latest patch we have to use the patch still, but the old patch is not working.

The attached in conjunction with #2741877-109: Nested modals don't work: opening a modal from a modal closes the original allows you to embed inside embeds. Tested 4 layers deep 🤯

Interdiff against #9

Yep, keeping an eye on that one too.

I'm not sure stacked modals is a great idea but 🤷‍♂️

Realised I left behind some cruft from an earlier attempt in the last patch, removed it

I've rerolled the patch and pushed that straight to the MR