Thinkpad S450 running 20.04 fully up-to-date. If I select the lock option from the top panel nothing happens.
The lock option from the top-panel calls a GNOME based function which effectively calls a SystemD thing … which again I imagine depends upon what the kernel is presenting to-do the lock.
Is this a new install ?
uname -a <— that should say what kernel you are using.
No, it was my fault had it turned off.