Quote:... I am using a Dell Precision 7760 laptop with a second LG 24 inch monitor, unfortunately not 4K. It is set to 1920X1080 as max resolution.
Dell Precision 7760 has three options for screen: 17.3-inch, 2 HD @ 1920 x 1080, 1 4K @ 3840 x 2160 with respective densities of 127 ppi and 255 ppi.
If Gimp is set up for 4k (laptop 255 ppi) and the second monitor is HD (??? ppi) then they will display differently
Gimp set at 256 ppi ?? What does the calibration setup in Gimp say ? That is physically measuring the rulers in the display. It is probably correct but worth a check.
Then it depends on which monitor shows the Gimp toolbox (I think, I do not have a dual monitor setup, only a lowly HD laptop with 158 ppi screen density)