Created attachment 798753 [details]
Config files

I installed the patterns Gnome and XFCE right after upgrading leap 15.0 to
15.1, and I have now the following menu entries in lightdm ( in this order ) :

  Gnome classic   
  Gnome on Xorg   
  Gnome           
  IceWM           
  Plasma          
  SLE classic     
  TWM             
  Xfce            
  Gnome           
  Plasma wayland  
  SLE classic 

Some menu entries do not start the right desktop/Xserver, as per the following
table :

NO! Gnome classic   : Plasma on Xorg
OK  Gnome on Xorg   : Gnome on Xorg
NO! Gnome           : Gnome on Xorg
OK  IceWM           : Icewwm on Xorg
OK  Plasma          : Plasma on Xorg
NO! SLE classic     : Plasma on Xorg
OK  TWM             : TWM on Xorg
OK  Xfce            : Xfce on Xorg
OK  Gnome           : Gnome on wayland
OK  Plasma wayland  : Plasma on wayland
OK  SLE classic     : SLE classic on wayland

I do not have any log in /var/log/lightdm since I upgraded ( which may be
another bug ? ) and nothing in systemd journal either.