STR: 1. Go to gmail 2. Create an account 3. Save login 4. Open a personal container tab 5. Notice login is auto filled The same behaviour is observed when creating the account in a container and used in a different container. In both situations I was expecting the login to be presented as a doorhanger to the input field rather than auto typed in. This would be a risk to users wanting to remain private across containers but have also chosen to use the password manager. If in a container the browser could refuse to autofill, this probably would be simpler in implementation than checking that the details came from the same container (however that could be a follow up bug, to autofill when the personal account is available in a personal tab).

If a username is prefilled in a Container, the website can read the username and identify a user who doesn't want to be identified in that Container.

It's not clear to me that using a container implies that I want privacy. e.g. if I'm in the "Personal" container why wouldn't I want it to autofill. I think this bug depends on the product decision of what containers are for. IMO this bug shouldn't be P2 "should be worked on in the next release/iteration" as I don't think it's clear what to do about this case (hence "consider" in the summary).

I think there are a few directions this bug could take: 1. Password credentials are tied to a container and are only autofilled in those containers they were assigned. - My personal gmail account is autofilled in personal tabs but not in work, where I might have a work gmail account auto filled. 2. Password credentials are not autofilled for any containers however by clicking in the fields I still get the option to fill 3. Users can choose to never autofill for all containers 4. Users can choose to never autofill per password Are there any risks in implementing 2. right now then moving to the other options later?

This is a P5 for the pwmgr component since containers aren't in release.

Bulk change per https://bugzilla.mozilla.org/show_bug.cgi?id=1401020

Closing in favour of considering this as the default for the browser in Bug: 1427543