Solved Facebook has my email address tho' I'm not a member. Security breach?

[Racundra]

Windows 7 with Firefox and Thunderbird.
How come Facebook has started displaying my email address (Yahoo) and a password in its login page? I've never had an account there. It shows a password too, which is obscured so I don't know what it is, and anyway it doesn't work.
I deleted all Facebook cookies and blocked any new ones; no change. Security breach somewhere? Maybe not serious, but unsettling. Thanks

 

[Callender]

You can see that obscured password using a simple trick but I'm not sure that it's okay to post the details here. Is it possible that someone else used your computer - assumed that you had a facebook account and attempted to login using your email and whatever they thought you might use for possible passwords? Check Firefox password manager and see which logins are remembered and stored if any.

See the section under "Viewing and deleting passwords" here:

Password Manager - Remember, delete, change and import saved passwords in Firefox | Firefox Help

 

[Racundra]

Thanks Callender for that. It's embarrassingly simple: Firefox password mgr contained a Facebook entry (though I don't remember putting there, and nobody else uses the computer). Deleted that, and all's well.
(As you rightly say, common sense is not so common.)