Affected Versions:
All latest Firefox versions: Nightly 96.0a1, Beta 95, Release 94

Tested on:
MacOS 10.15

Preconditions:

• browser.search.region DE
• extensions.formautofill.supportedCountries DE
• download latest Firefox Nightly with region locale (switch extensions.formautofill.available to "on" for testing non-Nightly builds)

Steps to reproduce:

1. Reach the payment form on zalando.de
2. Click on all the CC fields that toggle the CC dropdown
3. Hover over any CC entry saved and displayed in the dropdown

Expected Results:
During hover on a displayed entry from the CC dropdown, all the autofill eligible fields should be previewed as filled in.

Actual Results:
Only the focused field is previewed as auto-filled.

Notes:
Reproducible on Chrome: Yes
Regression-range: not a regressions, broken since Bug 1688576 where it was first reported

While these fields appear visually connected, they are separated by some iframes. The reason we don't highlight the other filled fields is because the browser is not filling them, the website is filling them from a hidden form. This is additionally why we don't preview other fields, they are being separated by hidden forms and/or iframes. Since these visible fields have no connection to each other, we don't preview or fill these fields.

From Bug 1688576:

The site itself seems to read the cc number from this 1px field and copy it to the credit card number field after we do our autocomplete work. This is why the fields don't highlight as if they have been autofilled, since credit card number isn't autofilled by us. As for why the name field doesn't receive the yellow highlight, there appears to be some inline styling on the input elements that override our autofill yellow color. See screenshot for more detail on the preview color issue.