Four Kitchens: Tips for upgrading to CKEditor5

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The Web Chefs

January 1, 1970

At Four Kitchens we keep several lists of “Hot Topics” to share our learnings across the dozens of sites that we care for. Are you upgrading a Drupal site to CKEditor5? We’ve tidied up one of these internal wiki documents into this set of general upgrade guidelines that might pertain to your website.

Rough steps to upgrade

The level of effort needed for this upgrade will be different for each site. It may take some time to figure out. CKEditor 5 is available in Drupal 9.5 and beyond. You can try switching/upgrading on a local site or multidev and assess the situation.

First, create a list of CKEditor enhancement modules on the site and check if they are Drupal 10 ready (the reports from Upgrade Status and this page may help). Common modules to look for include Linkit, Anchor Link, Advanced Link, IMCE, Entity Embed, Video Embed Field, Footnotes, and anything with the word “editor” in the title.

As a best practice, you should test both the creation of new content, and editing existing content in several places. This will help make sure that some lesser used HTML isn’t treated differently in the new CKEditor. Run visual regression tests (if available).

You may need to point out key interface changes to your clients or stakeholders (e.g., contextual windows for links/media/tables instead of modals, etc.). While it is a bit of a change, it’s overall an improved user experience, especially for new people who are coming in cold.

Anchor links

Anchor link gives editors the ability to create links to different sections within a page.

For “better integration with Drupal 10, CKEditor 5, and LinkIt” there is a 3.0.0@alpha version. If your project isn’t using wikimedia/composer-merge-plugin, you must require northernco/ckeditor5-anchor-drupal package and add the following to the repositories section of composer.json:

{ "type": "package", "package": { "name": "northernco/ckeditor5-anchor-drupal", "version": "0.3.0", "type": "drupal-library", "dist": { "url": "", "type": "tar" } } }



Embedded media

Depending on the age of your site, it might be using one of several techniques to embed media into the WYSIWYG:

If your site is using the video_embed_field module (most sites are probably using Drupal core’s media module), there is a patch that adds support for CKE5. Insert Image works slightly different (though this is probably not the case if your site uses core’s media module). It’s worth considering if there is a way to enhance this for user experience, if necessary.

If your site uses custom Entity Embed for media, consider switching to the core media library. It may provide a better administrative user experience in some cases.

The insert image button in CKEditor functions a little differently than it used to. Rather than bringing up a modal with fields to upload an image like the image below:

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It now immediately pulls up your computer’s file system for you to search for images like so:

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After adding your image, the alt tag box prompts you underneath the image:

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After submitting your alt tag, you can adjust alignment and sizing:

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Moving general styles to link styles

It was common in CKEditor4 to use its “Styles” feature to provide a way to add variations of links (to make them look like buttons, or to add icons).

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There are a few UX problems with that approach. Either the styles are set to apply on <span>, which means that they can be applied to non-links, or the styles are set to apply on <a>, which means that they are mysteriously grayed out most of the time (until you select a link). Either way, it’s not intuitive how to apply a link style. In CKEditor5, we can switch to using the Link Styles module.Image removed.

Change in Styles dropdown behavior

In CKEditor4, when integrated with Drupal, the Styles dropdown only allowed applying one style to an element (e.g., “external link”). If you tried to apply a different style, such as “locked link,” the previous style would be removed.

The Drupal implementation of CKEditor5 allows for multiple styles to be applied to elements via the Styles dropdown. This change may be unexpected for some, and could result in elements that look broken, such as when a link has both the “external link” and “locked link” styles.

CKEditor5 introduced a new API for adding theme-specific styles. The new architecture might cause the CKEditor5 theme to bleed into the admin theme. To know how to deal with these issues, review new API for adding theme-specific styles in CKEditor5.

You’ll likely run into an issue with styles bleeding outside of the editor, so see the other section within this page.

Cut and paste

Paste-from-Word, paste-from-Google-Docs, etc. is now built-in to CKEditor5. (At least for 90% of use cases.) There’s a paid plugin for more esoteric needs.

There is no paste-as-plain-text plugin for CKEditor5. You can use Ctrl-Shift-V (or Cmd-Shift-V) to paste as plain text. If you want to get rid of all formatting (including bold, links, etc.) in existing text, you can highlight the text, use Ctrl-C to copy, then Ctrl-Shift-V to paste it back as plain text.


Many of our Behat automated test broke after the update because there were multiple structural changes, so this is how we solved it: First, here is the doc about how to get the editor instance in case you want to know more about it. This is how we rewrite our custom step to fill out the CKEditor during testing. (We found the code in an article post-post).

/** * A step to help fill in a ckeditor wysiwyg. * * @param string $locator * The css locator of the field that ckeditor has taken over. * @param string $value * The html value you wish to fill in to ckeditor. * * @Then I fill in wysiwyg on field :locator with :value */ public function iFillInWysiwygOnFieldWith($locator, $value) { // $ckeditor5_drupal_editable_element = "div.form-item-$locator .ck-editor__editable"; $this->getSession() ->executeScript( " var domEditableElement = document.querySelector(\"$ckeditor5_drupal_editable_element\"); if (domEditableElement.ckeditorInstance) { const editorInstance = domEditableElement.ckeditorInstance; if (editorInstance) { editorInstance.setData(\"$value\"); } else { throw new Exception('Could not get the editor instance!'); } } else { throw new Exception('Could not find the element!'); } " ); }

and the mink step for regular field:

And I fill in wysiwyg on field "field-summary-0-value" with "Some Teaser Text"

And for a field inside a paragraph:

And I fill in wysiwyg on field "field-sidebar-content-0-subform-field-simple-text-0-value" with "Behat Side Nav Body Text"

Preventing custom styles from bleeding into admin theme with CKEditor5

See the new API documentation about implementing theme styles in the new way. This may require some adjustments on your end.

One of the major changes with CKEditor5 is that it pulls WYSIWYG styles onto the whole page when there is a WYSIWYG on the page. In CKEditor4, styles were only pulled into the CKEditor iframe. This can be extremely frustrating when the admin theme looks odd or different on pages that contain a WYSIWYG.

Limit the number of stylesheets being pulled into the WYSWIYG. (First, note that this method has only been confirmed to work on newer versions of Sous using specific webpack settings. If you are having problems with it, make sure your webpack settings allow for multiple manifests to be generated. You may need to refer to a newer site to see how it is configured.)

The first step is to create a new stylesheet (a manifest) called wysiwyg.scss in the same directory as your styles.scss file, which assembles all the stylesheets used in your theme. For this stylesheet, we’ll only want to include the stylesheets that our WYSIWYG needs. For example, I have one that looks like this:

@import url(',wght@0,400;0,700;1,400;1,700&display=swap'); @import '~normalize.css/normalize'; @import '~breakpoint-sass/stylesheets/breakpoint'; // Components @import '00-base/**/*.scss'; // Include all atoms except form items. @import '01-atoms/00-links/**/*.scss'; @import '01-atoms/01-text/**/*.scss'; @import '01-atoms/02-lists/*.scss'; @import '01-atoms/tables/*.scss'; @import '01-atoms/images/**/*.scss'; @import '05-pages/colors.scss'; @import '05-pages/base.scss';

In this example, we are pulling in a couple needed files from node_modules (normalize and breakpoint), and then any .scss files from base, and then select files from atoms (links, text, lists, tables, and images).

Compile and make sure that it has created the new files at /dist/css/wysiwyg.css. If you get any errors, you may need to include another file that has a variable you need, or something along those lines.

1.) Update your .info file In your theme’s .info file, set CKEditor5 to use your new stylesheet:

ckeditor5-stylesheets: - dist/css/wysiwyg.css

2.) Review the WYSIWYG. Visit a page with a WYSIWYG on the page, and verify that the limited styles are loading properly within the WYSIWYG. Try all the dropdowns and buttons that are included in the WYSIWYG settings. If anything appears unthemed, review your styles to see if there’s a stylesheet missing from your manifest.

3.) Review the rest of the page. Now review the page around the WYSIWYG and note how if differs from other pages that do not have a WYSIWYG. Common differences to look for are: heading styles, text styles, buttons — basically anything that you included in your manifest.

4.) Limit styles

  • Find the page’s body class for node edit pages (in our test case, .gin--edit-form). It may depend on your admin theme.
  • Find the wrapper class for the WYSIWYG. Most likely the best choice is .ck-content. Our approach will be to hide styles from .gin--edit-form, but then add them to .ck-content.

For example:

body { background-color: clr(background); color: clr(text); @include body-copy; }


body:not(.gin--edit-form), .ck-content { background-color: clr(background); color: clr(text); @include body-copy; }

And for buttons:

.main .button { @include button-base; @include button-color-primary; @include button-medium; }

it becomes:

body:not(.gin--edit-form) .button, .main .button, .ck-content a.button { @include button-base; @include button-color-primary; @include button-medium; }

With any luck, the styles used apply mixins, which makes it easy to filter out where to apply the styles. In some cases, the overriding of styles may become hard because of the order in which the stylesheets are loaded. Try to avoid !importants and instead use things like an additional element or class to firm up your override.

One issue that may come up is your overrides here end up overriding things in your custom theme, depending on how they are defined. In this case, don’t wrap the styles in the body classes, but rather undo the custom theme’s style on the admin page items manually. Luckily, since we’re narrowly applying custom styles, only things used in the WYSIWYG will need to be addressed.

For instance:

// Apply general link styles to all links. a { @include link; } // Overrides for Admin pages containing CKEditor (you will need a body class only on admin pages). .user-logged-in { a { background-image: none; transition: none; } .horizontal-tabs-list a, .toolbar a { font-weight: normal; } } // Reapply link styles to links within the WYSIWYG .ck-editor a { @include link; }

Continue to review your page and adjust it until it no longer differs from other admin pages.

Editor explodes out of its container in deeper paragraphs

This issue seems to occur only with rich text fields within a paragraph. It might be limited to the Gin theme.

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This issue might be because of the container’s width. If input fields inside the container have a specified size exceeding the screen width, it can lead the editor to inherit the container’s width, extending beyond the screen. You can see this as a Drupal Core/CKEditor5 bug in CKEditor5 toolbar items of multivalue field (typically Paragraphs) overflowing on narrow viewports and overlapping with node form’s sidebar on wide viewports.

To resolve this quickly, set the input fields to 100% width, making sure everything works seamlessly. Be sure to include this in a stylesheet of your admin theme.

.node-form input[size] { width: 100%; }

We can also modify the ‘flex-wrap’ property of the CKEditor buttons to make sure they stay within the container’s width:

.ck-editor > .ck-toolbar__items { flex-wrap: wrap; }

Additional resources

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