macOS Mojave 10.14.5
I've just upgraded to a new iMac with retina display

The grid for live rotation at first sight appears to have vanished. However, if after selecting Live Rotation, I then zoom in on the image, the grid becomes visible but the lines are very thin.
I guess this is because of the much higher resolution of the display and when the grid is superimposed on the image, the grid lines are only 1 pixel wide?
Perhaps a control for seting the grid line width?
regards,
Larry