drupal.js?v=10.4.1:64 Uncaught TypeError: rowHandlers[data.rowHandler] is not a constructor

@drupol, I am unable to replicate the issue for both drupal/field_group:^3.6 and drupal/field_group:^4.0@alpha. It could be an issue with another module and not caused by this module. Additionally, can you provide the contemt type for which you are getting this issue and also attach a screenshot of the error.

Hello @drupol,

I tried to replicate the issue you reported after clicking the "Add field group" button (Structure > Content Type > Manage Form Display), but I couldn't reproduce it on my end.

Here’s what I tested:

Cleared caches using drush cr and cleared browser cache.
Tested with both field_group versions: 3.6 (stable) and 4.0.0-alpha1.
Verified compatibility with Drupal Core (10.4.1 in my setup).
Checked for any JavaScript errors in the browser console, but found none.
The functionality worked as expected without throwing the rowHandlers[data.rowHandler] is not a constructor error.

If the issue persists for you, it might be related to your environment or customizations. I recommend:

Clearing caches again (drush cr).
Checking for JavaScript conflicts caused by other modules or custom scripts.
Verifying that all module files are installed correctly by running composer install.
Testing in an incognito/private browser window to rule out cache issues.
If the problem continues, it could help to share more details, such as your exact Drupal version, enabled modules, or any customizations applied to the field UI.

Let me know if you need further assistance!

Hello @drupol,

I tried to replicate the issue you reported after clicking the "Add field group" button (Structure > Content Type > Manage Form Display), but I couldn't reproduce it on my end.

Here’s what I tested:

Cleared caches using drush cr and cleared browser cache.
Tested with both field_group versions: 3.6 (stable) and 4.0.0-alpha1.
Verified compatibility with Drupal Core (10.4.1 in my setup).
Checked for any JavaScript errors in the browser console, but found none.
The functionality worked as expected without throwing the rowHandlers[data.rowHandler] is not a constructor error.

If the issue persists for you, it might be related to your environment or customizations. I recommend:

Clearing caches again (drush cr).
Checking for JavaScript conflicts caused by other modules or custom scripts.
Verifying that all module files are installed correctly by running composer install.
Testing in an incognito/private browser window to rule out cache issues.
If the problem continues, it could help to share more details, such as your exact Drupal version, enabled modules, or any customizations applied to the field UI.

Let me know if you need further assistance!

This a duplicate of https://www.drupal.org/project/field_group/issues/3491233 🐛 Drupal 10.4 RC1 error with field_ui.js Active . There is a working patch in there.