Gnome screensaver lock always responses "incorrect password" when last active window's language is not the language of the password

[Andrew Frolikov]

Environment:
OS - Ubuntu 16.04.2 LTS, DE - GNOME Shell 3.20.4, lightdm, gnome-screensaver 3.6.1

Prerequisites:
 - say, you have 2 language layouts installed
 - their layouts/character tables are completely different, so there is no chance you can type your password correctly using any language keyboard layout (e.g. you have en/ru, but not en/de etc.)

Actual behavior:
When the screen is being locked while your active window has the language which is not your password language set, you won't be able to log in back. Log in form shows that the language of the password is set (EN in my case) but it always returns 'Incorrect password' message in response to the correct input. Switching language layout using the keyboard shortcut or GUI doesn't help.
'Switch user' trick allows you to log in back though, but it's a crutch.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Didier L (l-farquaad)]

Same here: you have to remember which layout you were using before switching, and type your password in that layout… if that is possible.

Seems to be a duplicate of #1612910

[Mantas Kriaučiūnas (mantas)]

Gnome-screensaver shouldn't be running on GNOME Shell. It's 5 years old software and is needed only for old GNOME flashback (fallback) session.

[Andrew Frolikov (frol3000)]

I hadn't mention that I've been using lightdm. After switching to GDM the issue was resolved.

[Tamer Hassan (tamer.hassan)]

Indeed, this issue only occurs to me when using lightdm. only then does gnome-screensaver kick in. otherwise, gdm3 handles both login and lock screen