Master password behaviour changed?

I found a usb key that i used John's awesome Portable Firefox on years ago. I had a master password set. I notice that when I first start up Firefox it immediately asks for the master password.

I downloaded the latest apps suite program and installed the new Portable Firefox. I set a master password but it doesn't prompt you for it until you go to a site needing login details. It seems you can use the browser to your heart's content as long as you avoid a login page. This means someone can browse all your bookmarks also.

Am I right that it has been changed or am I missing some option that I set years ago? I prefer the old way where you had to enter it immediately. I downloaded Opera and it seems its master password works the new way as well. Moreover if I login somewhere and don't log out the next time either browser is started you're still logged in!