Forms: use a dropdown selector to list eligible users for notifications

[vianasw]

Fixes FORMS-351

To make it easier to select users in the form notification settings, I'm using the FormTokenField dropdown selector variation, which will list all the eligible users we can send notifications to.

Proposed changes:

• Added __experimentalExpandOnFocus option to make the FormTokenField component behave like a dropdown selector.
• Added __experimentalAutoSelectFirstMatch option to automatically select the first match when you hit enter.

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
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Jetpack product discussion

Does this pull request change what data or activity we track or use?

Testing instructions:

Before	After

• Enable the feature flag jetpack_forms_enable_notifications.
• Create a form and enable the toggle Enable notifications for responses in the forms block sidebar Form notifications panel setting.
• Click on the input under Send notifications to and confirm that a list of users is displayed.
• Select some users and confirm that the notifications are sent to those users on each form submission.

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WoA dev site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin (Jetpack), and enable the update/form-notification-recipients-input branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack update/form-notification-recipients-input

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[github-actions]

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Code Coverage Summary

This PR did not change code coverage!

That could be good or bad, depending on the situation. Everything covered before, and still is? Great! Nothing was covered before? Not so great. 🤷

Full summary · PHP report · JS report

[simison]

Can you add screenshots to the PR as well? Thanks!

[simison]

Overall works, but this "can't remove last" is a bit clunky:

Screen.Recording.2025-10-29.at.15.13.05.mov

Not sure what should we do about it tho. Allow leave input empty, effectively disabling the feature?

[vianasw]

Overall works, but this "can't remove last" is a bit clunky:

Screen.Recording.2025-10-29.at.15.13.05.mov
Not sure what should we do about it tho. Allow leave input empty, effectively disabling the feature?

I have mixed feelings about this one too. It's either disable the feature if we leave it empty or default add the post author. I'd suggest merging this and sleeping on it in case we want to change it.

[simison]

Yep not a blocker for merging — can you pass it by Ilona in case she can solve it?

[ilonagl]

Thanks for the ping!

The functionality makes sense, we don't want users to leave this empty. The missing piece is communication, so users understand what is happening. Would it be possible to change the helper text to explanation one when user tries to remove user? Like show a red helper text saying that you need at least one recipient for notifications to work?

[ilonagl]

And do we need to a drop-down if there is only one user?

[ilonagl]

If we could align the helper text in both inputs (update the first one to 'Separate with commas or the Enter key.') It would be great!