Pressing Enter in Add Filter dialog results in "Leave page?" prompt

[djast]

Describe the bug
In the Settings -> Filters -> rainloop.user -> Add a Filter dialog, pressing Enter in the Name field results in a browser warning; e.g., "This page is asking you to confirm that you want to leave -- information you've entered may not be saved" in Firefox, or "Leave site? Changes [that] you made may not be saved" in Microsoft Edge or Chrome.

To Reproduce
Steps to reproduce the behavior:

1. Go to Settings -> Filters
2. Click on rainloop.user
3. Click "Add a Filter"
4. With the cursor in the Name field (or, with Firefox, with keyboard focus on one of the checkboxes, e.g. "Mark as read" or "Stop further processing of files"), press Enter.

Expected behavior
The browser should not attempt to submit the form or otherwise navigate away from the page. The keyboard focus should probably move to the next field (as if the user had pressed Tab rather than Enter).

Please complete the following information:

• Browser: Firefox 102, Chromium 110.0.5481.77, Microsoft Edge 110.0.1587.41
• IMAP daemon: dovecot
• PHP version: 7.4.33
• SnappyMail Version: 2.27.3
• Mode: standalone; also at https://snappymail.eu/demo