Authenticate force_login & screen_name parameters



I’m using with force_login=true optional parameter and it works well. Now I have a particular usecase where I want to re-authenticate user and to do it for specific twitter screen_name. The idea is that user has to enter just a password, while username to be pre-filled.
Problem is that if I build authenticate url and use screen_name parameter in addition to force_login=true I’m not prompted to enter a password when I’m already signed in with the same screen_name used in authenticate url:

I find this strange, because I would expect that current twitter session shouldn’t make a difference and if force_login parameter is present that user must enter a password.

Let me know your thoughts…

Thanks a lot