AJAX error prevents user from creating a form

Please check the browser console log and Drupal’s log for errors occurring at the same time.

Are the entire steps to reproduce from installing Drupal verified?

Is this anything to do with 🐛 Ajax behaviour on entity edit form action buttons can break Needs work ?

I've tested this in Claro and it happens there too. However, there must be something unique to my website's set up because I tried recreating this on a vanilla Drupal site and was able to create a new webform without issue.

Marking this as Postponed, maintainer needs more info while I look into other conditions that are contributing to this issue.

I had this issue also with Gin 3.0.0-rc9 and Webform 6.2.2 on Drupal 10.2.4.

Following the advice in #3, I found that when I first click the 'add webform' button, I get the errors:

Refused to apply style from 'https://my.site/libraries/path/to/editor-styles.css' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.

An error occurred during the execution of the Ajax response: The following files could not be loaded: /libraries/path/to/editor-styles.css

Clicking a second time calls up the form, but I get the "ajaxSubmit is not a function" error when I try to submit.

It turns out that my default theme and its parent declare a CSS file for ckeditor5 in its libraries.info.yml:

ckeditor5-stylesheets:
  - /libraries/path/to/editor-styles.css

For whatever reason, Drupal isn't recognizing this as a library and is serving it with the wrong MIME type header. I found a workaround in a possibly related Drupal issue: 🐛 Stylesheets in 'ckeditor5-stylesheets' are not checked for existence before being included Active .

I removed the ckeditor5-stylesheets key and move it to libraries-extend in the theme.info.yml file:

libraries-extend:
  core/ckeditor5:
    - /libraries/path/to/editor-styles.css

I could also mitigate this for *webform* by changing the HTML Editor settings in Configuration -> Elements.

This isn't the only place on the site I see the error - I get it wherever there is a Ckeditor5 editor, even when I switch the admin theme to Stark or Olivero. But it is the only place I can find where the MIME error breaks an AJAX submit later on in the interactoin.

So I think there are two issues:

1. Drupal is not sending the right header for editor CSS files defined in a theme info file using the ckeditor5-stylesheets key. I'll search around and create a new issue if necessary.
2. Some additional error handling for Webform AJAX calls would be nice.

Ack, I can't duplicate my Drupal issue. It seems most likely that I had the path wrong in the .info.yml file. It makes sense that my local issue was the same as 🐛 Stylesheets in 'ckeditor5-stylesheets' are not checked for existence before being included Active .

But regardless, this caused an AJAX error when the 'add webform' form loaded, and eventually the form would not submit, and I think we could prevent this and future random problems with some additional error handling.

But regardless, this caused an AJAX error when the 'add webform' form loaded, and eventually the form would not submit, and I think we could prevent this and future random problems with some additional error handling.

It is difficult to prevent Ajax from failing when a random error occurs on the pages. Hopefully, Drupal will refactor or improve its Ajax API at some point.