Yes, I use the same single password for both system root and (i3) user. 
Providing that same password to the dialog box allows me to proceed normally from there. (And to confirm, I have not changed this password.)
Yes, I use the same single password for both system root and (i3) user. Providing that same password to the dialog box allows me to proceed normally from there. (And to confirm, I have not changed this password.)