I have tightvnc server on my new ubuntu-22.04 machine and can use vnc.
VNC xstartup is configured to use Xfce4.
How can I disable the automatic screen lock of the Xfce4 window?
I tried setting 'Display Power Management' to 'off' in Applications->Settings->Power Manager menu, but it doesn't work.
Have you disabled Xfce screensaver?
xfce4-screensaver-preferences
will let you control locking the screen on inactivity, and includes options to either leave the screen blank or use a graphic-screensaver (which helped prevent burn-in if using a monitor where that was a risk; and long ago it used to be a major risk).The power management you mention turns the screen off to save electricity (battery life etc).