Confirmed that the --desktop options does not really work. Can be tested by adding a second virtual desktop and starting whatever program with kstart5 --desktop 2 --windowclass foobarbaz konsole etc.
Needs to go upstream I guess. Norbert -- PREINING Norbert https://www.preining.info Fujitsu Research + IFMGA Guide + TU Wien + TeX Live + Debian Dev GPG: 0x860CDC13 fp: F7D8 A928 26E3 16A1 9FA0 ACF0 6CAC A448 860C DC13