Here https://support.google.com/docs/answer/2405894 I read I can sign in multiple Google accounts and easily switch between them in Google Docs app. But it is not true. It doesn't work. I'm talking about desk top version now, not mobile.
I can sign in more than one account but I cannot switch between them. Google forces me to sign out current account to be able to sign in other one.
Here is a screenshot I'm really signed in three accounts:
And instead of just switching me other account I'm asked to sign out current first:
How to enable mechanic explained in docs? Or is it explained in docs only but not available in real life?