So today I wanted to try FF Containers, because I have service user to manage O365, my normal company user and my personal user. Now I open make.powerapps.com in container dedicated to this site I log in with one of these users everything is ok, but during first sign-in I am not asked even for password for specified account, I just enter email and then I am redirected and signed in. I have disabled "Allow Windows single sign-on for Microsoft, work, and school accounts". When I want to access portal.azure.com in another container, I am automatically signed in with user from previous container dedicated to powerapps. I especially logged out of all containers and removed all cookies from FF before submitting and it is still happening Also checked Windows "Internet options", I do not have any of these sites in "Intranet sites" and Level for all zones regarding to User Authentication is "Prompt for user name and password" dunno know what is wrong.