Greeter sometimes fails to set Admin password on Stretch
First reported by u in https://labs.riseup.net/code/issues/12364#note-1
> So the window opens in a weird location after clicking “+”.
> Then I enter the password and click “Add”.
> Then the option window closes and the option seems set, but it’s marked as “off”.
> When i reclick a second time on the option I get a window bubble with the password and the password confirmation. I click enter and then it is set to on.