Comment # 2 on bug 1154126 from Frank Kruger

Unfortunately, after a reboot the issue is back (TW20191016), i.e.,
hplip-systray (hplip-3.19.6-2.1.x86_64) is always shown, although it is
configured as "Hide when inactive". When I open "Settings" and just press "OK"
the icon disappears after few seconds, as expected.