It's worth mentioning that Google didn't enforce the option in iGoogle until now, even if the setting to force the secure connection was added last year. There are many incompatibilities between the HTTPS setting and Google applications like Google Toolbar, Gmail Notifier and the mobile Gmail application, which weren't design to support this option.
Here's Google's explanation:
As several of you have noticed, we made a change in iGoogle to the way that iGoogle's Gmail gadget works. If you previously set Gmail to only access your mail using https by selecting "Always use https" in Gmail's settings, you will now see a message in iGoogle's Gmail gadget asking you to open the full version of Gmail. We made this change in iGoogle for those users who want to ensure that their Gmail is transmitted using https.
We know that many of you would like to access your mail from iGoogle with https, and we're investigating ways to provide https support for iGoogle's Gmail gadget. In the meantime, you have a couple of choices:
- If you'd prefer to access your mail with https, please visit Gmail directly at https://mail.google.com/mail.
- If you'd rather get your Gmail on iGoogle with the Gmail gadget, visit Gmail's Settings page and select "Don't always use https."
I think it's great that Gmail supports secure connections, a feature that's not available in other popular webmail services like Hotmail and Yahoo Mail. The option to always use HTTPS is just an added bonus, since you can easily bookmark https://mail.google.com/mail/ and use that URL. To prevent the incompatibilities, Google could add independent HTTPS settings for all the applications and services that use Gmail, so that the gadget or the notifier work even if you've enabled "always use HTTPS" in the desktop version of Gmail.
{ Thanks, Simon and Michael. }