Consider replacing our custom window-center GNOME Shell extension with the center-new-windows Mutter option
When we did fix window centering (!970 - merged), I don't think we were aware of the Mutter option used in !1068 (closed).
Could we enable this option in the Welcome Screen as well (config/chroot_local-includes/usr/share/gdm/dconf/50-tails
), and drop our custom extension?
I think we should do that next time our custom extension causes trouble.