With gdm version 3.28 selecting the (previously working) option for a plasma
session on Wayland returns us to the gdm login screen.

$ cat /etc/os-release 
NAME="openSUSE Tumbleweed"
# VERSION="20180314"
ID=opensuse
ID_LIKE="suse"
VERSION_ID="20180314"
PRETTY_NAME="openSUSE Tumbleweed"
ANSI_COLOR="0;32"
CPE_NAME="cpe:/o:opensuse:tumbleweed:20180314"
BUG_REPORT_URL="https://bugs.opensuse.org"
HOME_URL="https://www.opensuse.org/"

$ rpm -q gdm                                                                    
gdm-3.28.0-1.1.x86_64

Bug ID	1085772
Summary	gdm 3.28 cannot start plasma session on Wayland
Classification	openSUSE
Product	openSUSE Tumbleweed
Version	Current
Hardware	Other
OS	Other
Status	NEW
Severity	Normal
Priority	P5 - None
Component	GNOME
Assignee	bnc-team-gnome@forge.provo.novell.com
Reporter	roger.whittaker@suse.com
QA Contact	qa-bugs@suse.de
Found By	---
Blocker	---