refresh rate falling back after i close window

video. my refresh rate goes back to 60hz even if i change it in the gnome settings. the video(sorry for the slideshow) shows it. I use 1920×1080 and display port. my gpu is rx 480 nitro+. i have already tried setting it via xrandr. xrandr:

Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384 DisplayPort-0 disconnected (normal left inverted right x axis y axis) DisplayPort-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 544mm x 303mm    1920x1080     60.00*+ 144.00   119.98    99.93    50.00    59.94      1680x1050     59.88      1280x1024     75.02    60.02      1440x900      59.90      1280x800      60.00      1280x720      60.00    50.00    59.94      1024x768     119.93    99.99    75.03    70.07    60.00      832x624       74.55      800x600      119.93    99.86    72.19    75.00    60.32    56.25      720x576       50.00      720x480       60.00    59.94      640x480      119.80    99.83    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) HDMI-A-1 disconnected (normal left inverted right x axis y axis) DVI-D-0 disconnected (normal left inverted right x axis y axis)