It happened when I unpluged a external 4k monitor. Rebooting and seting xrandr are useless.
screenshot:
100% scaling: window big, side bar normal
200% scaling: both too big
xrandr --output eDP-1 --scale 2x2: window back to normal scale but the pointer is scaled 200% too and reset back after restart.
xrandr --output eDP-1 --scale 2x2
xrender
xrender
can temporarily solve it. – fishyman Sep 04 '20 at 11:15