Regression: Double submit prevention breaks with JS

+1

Tested on Drupal 7.100 with PHP 8.1. The proposed fix is appropriate and tackles the issue effectively.

Thanks for reporting this.

I think the main reason we skipped this additional code was, that the D9+ code has the same implementation without the event.isDefaultPrevented() (see the current Drupal 11.x-dev code: https://git.drupalcode.org/project/drupal/-/blob/11.x/core/misc/form.js). There is an issue for D10 still open #3251249: Should double-click prevention return early when isDefaultPrevented? → . I think we need to decide and solve this for D10 first. If there will be a decision to add this code, we can add this to D7 as well. Without it, I am not sure if we are going to change a way how it works, as it will be a bit different in D7 and D10 then. So if possible, please focus on the D10 issue and then we can mode here as well. Thanks!