In suse's default settings there is this 'application menu' on the bottom left
with search, apps, shortcuts and reboot, shutdown and logout options. when
clicking one of the options, a full screen dialog pops up with a countdown and
again those options (+in my cases a suspend option was added).

this is illogical, as all those shutdown and logout options are offered twice.

This can be changed in system settings -> Startup and shutdown -> desktop
session -> Offer shutdown options (untick) or - same page - Confirm login

the result of the former is, that only one icon is shown in the 'application
menu'. the same goes for the 'application dashboard' (which is an alternative
to the 'application menu').

the result of the other is, well, the second screen is gone.

'application launcher' is only consistent with confirmLogout=false and
offerShutdown=true

the option is stored in "~/.config/ksmserverrc"
[General]
confirmLogout=true
offerShutdown=false