(In reply to Ronny Peine from comment #7) Hello Ronny, here is the test report: 1. I checked that screen saver was in state "Disable Screen Saver" and killed xscreensaver. 2. In an xfce terminal I repeatedly entered the command "xset dpms force suspend". 3. The first three attempts produced the same result as force standby: Both monitors blank for 1 second and then the previous display returns to both monitors without any action by me. 4. Fourth attempt: both monitors go blank with blue power indicator. DP-2 (2nd monitor) returns with its previous display. DP-1 (1st monitor) stays blank. Moving the mouse has no effect on DP-1, it stays blank. 5. I rebooted the machine, and killed xscreensaver. 6. In an xfce terminal I repeatedly entered the command "xset dpms force suspend". 7. The first 12 attempts produced the same result as force standby 8. 13th attempt: the monitors blanked for 10 seconds before both diplays resume. 9. The next 17 attempts produced the same result as force standby 10. 31st attempt: the monitors blanked for 10 seconds before both diplays resume. 11. At least 20 further attempts produced the same result as force standby. 12. (Same as 4 above) Both monitors go blank with blue power indicator. I do not touch the mouse. After about 10 seconds DP-2 (2nd monitor) returns with its previous display. DP-1 (1st monitor) stays blank. I now move the mouse - this has no effect on DP-1, it stays blank. I can see the mouse movement and type into DP-2 but DP-1 cannot be used. Best Regards, Roger