Closes #5275 Adds Mercury Editor 3.0.0-alpha13

[ewlyman]

Description

Adds the Layout Paragraphs and Mercury Editor modules to Quickstart

Release notes

Related issues

Closes #5275

How to test (please read all instructions as our options have changed)

1. Enable Mercury Editor -- you will be prompted to enable dependencies, it's safe to do so.
2. Under Configuration, go to Mercury Editor settings and select Page and Person under "Content" and save configuration -- these two content types are useful for demonstrating M.E. but you can also try others.
3. Under Configuration -> Performance clear all caches
4. Visit any Page or Person content and select "Edit" to test the editor interface
5. Add page content. By selecting the + sign, you should see a list of paragraph types you can add to the page.
6. While editing in the system tray on the right side of the screen, you can view your updates immediately in the WYSIWYG display on the left. You can resize the system tray to a comfortable editing size and then minimize it for content review, if you prefer.
7. Remember to click "Save Changes" in the top right corner before exiting Mercury Editor. Otherwise you will lose your changes.

Types of changes

Arizona Quickstart (install profile, custom modules, custom theme)

• Patch release changes
  • Bug fix
  • Accessibility, performance, or security improvement
  • Critical institutional link or brand change
  • Adding experimental module
  • Update experimental module
• Minor release changes
  • New feature
  • Breaking or visual change to existing behavior
  • Upgrade experimental module to stable
  • Enable existing module by default or database update
  • Non-critical brand change
  • New internal API or API improvement with backwards compatibility
  • Risky or disruptive cleanup to comply with coding standards
  • High-risk or disruptive change (requires upgrade path, risks regression, etc.)
• Other or unknown
  • Other or unknown

Drupal core

• Patch release changes
  • Security update
  • Patch level release (non-security bug-fix release)
  • Patch removal that's no longer necessary
• Minor release changes
  • Major or minor level update
• Other or unknown
  • Other or unknown

Drupal contrib projects

• Patch release changes
  • Security update
  • Patch or minor level update
  • Add new module
  • Patch removal that's no longer necessary
• Minor release changes
  • Major level update
• Other or unknown
  • Other or unknown

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.
• My change requires release notes.

[ewlyman]

@elyssanaval encountered an issue on 02/17/2026 where Mercury Editor and Workspaces are incompatible (breaks page editing).

@joshuasosa found the specific issues on Drupal.org as follows:
https://www.drupal.org/project/mercury_editor/issues/3495098
https://www.drupal.org/project/layout_paragraphs/issues/3472181

The patch linked at https://www.drupal.org/files/issues/2024-12-19/drupal-10.3.x-mercury_editor-workspaces-comment-2.patch addresses the breaking issue with editing when both Mercury Editor and Workspaces are enabled. However, the patch is actually a core/drupal patch, even though it is labelled for ME.

So our current status is as follows:
Layout Paragraphs' modal editing form returns this message if you use it inside a Workspace: This form can only be submitted in the default workspace. Edits made to fields in the Mercury Editor side tray, however (including paragraph reference fields), save just fine --both inside a Workspace or out of one.

This strongly suggests we'll need to see if the incompatibility between Layout Paragraphs and Workspaces can be addressed, or if moving to Mercury Editor 3.x will provide us with some alternatives.

Testing 3.x.alpha for M.E. is my next step.

[ewlyman]

Updated branch to Layout Paragraphs 3.x and Mercury Editor 3.x. Real time changes to page content are now reflected in the WYSIWYG section of Mercury Editor. Have also updated instructions for testing PR.