preview window

Can you try toggling View Material in the Parameters Tab to see if that makes any difference.

Right Phill !! view material unchecked works

This is going to be difficult to fix because I cannot see the issue on any of my machines, you may have to bear with us for a while.

Can you run the following command line commands:
linuxcnc_info
sudo lshw -C video > /tmp.video.txt
glxinfo > /tmp/glx.txt

Then post the following files:  /tmp/linuxcnc_info.txt   /tmp.video.txt  /tmp/glx.txt


 

it's the least I can do for you. the video card is integrated, but I tried to disable it and put a nvidia gt 520 without any difference here are the files