Unable to login to GNOME Shell xorg session while Wayland session works properly

[Farhad Mohammadi Majd]

*** SOLVED ***

== Solution ==
Ran following command in the system console:

#apt autoremove

a lot of packages related to the flashback session were removed, and
after rebooting the system, I am able to log-in to xorg session.

on Wed Jun 5 07:44:29 UTC 2019, Colin Law wrote:

> Try this, which should make sure all the packages needed for the
> desktop are there
> sudo apt install ubuntu-gnome-desktop
> 
> If still no joy, does it work if you login as a different user
> (create
> a test user if necessary)?

1. I don't like to install unwanted packages, even "no-install-
recommends" is used/enabled always; and "GNOME Shell on xorg was
working well for weeks, until ...."

2. This test failed.