This is the PostToInsecureFromSecureMessage:
"Although this page is encrypted, the information you have entered is to be sent over an unencrypted connection and could easily be read by a third party"

The "PostToInsecureFromSecureMessage" warning can't be suppressed, it is too important.
You will get that warning if you go from a secure https connection to an insecure http connection and POST data entered in a form on a secure site is send to an http server.

The warning tells you that you are sending data from a secure site to a non secure http url.
You can usually avoid such an alert if you directly go to the login page and not via a link on the http home page that has a redirect back to that page once you have logged on via a secure https connection.

Please tell this to the folks (at Microsoft) who run login.live.com; it's getting really annoying...

[and boy does this page looks awful in IE7, which I am using because FireFox is being unresponsive at the moment for some reason...]

It is not so important that it cannot be disabled or have an option to always trust a site! It is assanine and an annoyance. I am sick of Firefox and IE7. Chrome is not an option as I do not agree with its developers' views.

Give me an option to stop the stupid warning: Although this page is encrypted, the information you have entered is to be sent over an unencrypted connection and could easily be read by a third party.

Are you sure you want to continue sending this information?

I know I can trust sites and I do not need big brother to do it for me!

I agree with criminalist - IE7 actually does have an option to ignore this warning for trusted sites, and it works quite well thank you. And, by the way, Firefox also used to have this option, because I had the warning turned off in 3.6, which was also working just fine thank you. Now all of a sudden, it's showing up in Firefox 7, with no option to turn it off.

And cor-el, your response doesn't really make sense here. I'm seeing this warning every time I go from an https: page to an http: page - after I've logged onto the secure page - because the site doesn't have the content I want to view on their secure site. Please don't suggest I contact the administrator of that site, because that's just retarded. They're not going to pay any attention to such inquiries, or they'll tell me to ask Firefox to allow us to turn this annoying warning off - which is exactly what should be done. If there isn't a solution to this problem soon, I'll be switching back to IE or Chrome.

Don't even try to tell us this was done intentionally - it's obvious it was a programming/testing miss, because there is an override switch in about:config, but it just doesn't work. Just admit it was a mistake and fix it in the next release!

Maybe I should have said that I have Firefox set up to log into my home page (MSN.com) when I first log on. I am not leaving one page for annother, I am starting up Firfox and it should automatically log into my home page. I do occasionally get this message when moving from one page to another, which I guess is okay but it is very annoying to come back to my computer when I click on Firefox and find it was hung up on this stupid message. My computer is slow so I often leave the room when logging on. Not the end of the world but it sure seems like something easy to fix.

The problem is that you entered data on a secure site that you would expect to be kept secure and not exposed as it will be if you pass that data to a non secure http link. That can be a severe security risk in some cases and Firefox warns you about this. It is the same as with resending POST data if you use the Back key and both those alerts can't be suppressed. If it is a link that you can copy to the clipboard then you can open a new tab and paste the URL in the location bar to avoid that.

I'm using XP with Mozilla as my default browser. I downloaded Firefox on Aug.11,2011. I don't get this message using IE.

"directly go to the login page and not via a link on the http home page" I get the message window every time I try to login through the login page (it's the only way to log in). When I get the message window, I click continue the login page reloads and the login attempt fails. How do I get around that?