Square box around mouse pointer on kubuntu 16.04 and nvidia 960m

Question

Got the well known issue with the nvidia driver on a ASUS GL552v. Current issue: After changing back to 16.04 on Kernel 4.15.0-30 found the square around mouse pointer as also mentioned in question 947375. Managed to temporary solve it by using sudo systemctl restart sddm But I would prefer a permanent fix and already tried the suggestion of re-installing x-org files. Unfortunately no success in fixing problem. Any ideas for a permanent fix?

For those who want to know - How I got to this point: Had an earlier version of 16.04 working fine for over 1.5 years after overcoming initial installation problems by removing second hdd and using the 'nomodeset' command. Then, after successfully installing 18.04 on 3 laptops I've decided its now time for my own to get a clean install and upgrade to 18.04. Only to discover the lagging problem in regards to problems with nvidia driver. After many hours of not finding any solution decided to go back to 16.04

Answer 1

I have been using Kubuntu 18.04; when I tried a Windows technique to enlarge the whole screen (two keys: 'windows/start' '=', I get a mouse pointer with a square black frame (about 2" sq.) with a solid black picture of an enlarged computer screen that will follow the pointer (with a time lag of the screen changing as I move the pointer around the screen)

A reboot would not get rid of the square picture around the mouse pointer. I searched the internet for a solution; I found a partial solution:

"System setting->Display and Monitor->Compositor>open GL2.0} change to XRender> then Apply"

That got rid of the solid picture, I still had the black 2" square with a magnifier inside following the mouse pointer (without a time lag). After playing with the different adjustments inside the Compositor, I discovered:

"turn the [Enable compositor on startup] button off> then Apply and then reboot the computer"

That returned the mouse pointer back to normal!