I use Ubuntu 18.04, on Dell XPS 15. There is a huge difference in the resolution of my screens, so when I plugged external monitors, either everything was too big on external monitors or everything was so small on laptop monitor. I used xrandr to setup the scaling as follows:
xrandr --output eDP-1 --scale 1x1 --pos 0x2400 xrandr --output HDMI-1 --scale 2x2 --pos 0x350 xrandr --output DP-2-8 --scale 2x2 --pos 2560x0
eDP-1 is the laptop monitor with resolution 3840x2160, HDMI-1 is a VGA monitor with resolution 1280x1024, for which I use a VGA to HDMI converter to connect and DP-2-8 is another monitor with resolution 1920x1200 connected via display port. After doing this, mouse pointer started to blink, and even disappear only on eDP-1 but not on other screens, when CPU is in use. Let's say I open the settings window for Bluetooth, I cannot see mouse pointer, if I open an email, it blinks a couple of times and stabilizes. Does any one have similar problems or any idea what's going on?