Whenever I toggle my monitor (or it wakes up from standby) my refresh rate resets back to 60hz (from 144hz). This seems to be somewhat related to 10459, so I assume that the RRScreenChangeNotify event is responsible. When rebooting the computer normally, the problem doesn't appear and xfce4-settings remembers the correct refresh rate, which points even more at the RRScreenChangeNotify event. I am using an Nvidia GTX 1070, but neither setting the refresh rate from within XFCE, xrandr, or nvidia-settings, doesn't make a difference. I also tried setting things via xorg not no avail.
I have the same problem with a 75 Hz monitor that goes back to 60 Hz after a wake up or when it is switched on. With xrandr -q I found that the preferred mode sent by the screen is 60 Hz maybe a reason why xfce chooses to return to this value? alexis@qoo:~$ xrandr -q Screen 0: minimum 320 x 200, current 2560 x 1440, maximum 16384 x 16384 DisplayPort-0 disconnected (normal left inverted right x axis y axis) DisplayPort-1 disconnected (normal left inverted right x axis y axis) DisplayPort-2 connected 2560x1440+0+0 (normal left inverted right x axis y axis) 725mm x 428mm 2560x1440 59.95 + 74.97* 1920x1200 59.95 1920x1080 60.00 50.00 59.94 1600x1200 59.95 1280x1440 59.91 1680x1050 59.95 1280x1024 75.02 60.02 1440x900 59.89 1280x960 60.00 1280x800 59.95 1280x720 60.00 50.00 59.94 1024x768 75.03 70.07 60.00 832x624 74.55 800x600 72.19 75.00 60.32 56.25 720x576 50.00 720x480 60.00 59.94 640x480 75.00 72.81 66.67 60.00 59.94 720x400 70.08 HDMI-A-0 disconnected (normal left inverted right x axis y axis) Anyway, I have found a bad solution which is to disable the DDC/CI function of my monitor, so that it remains at 75 Hz after a wake up, but not after a power on/off.
You can now save a profile for your display so the "preferred mode" gets overridden by it.