Mouse (System Global) - wrong values on 2nd screen for differently sized screens

Mouse (System Global) displays wrong value output for the second (third, fourth, …?) screen, if they are differently sized like so:

The screen (2) is the main screen, and as soon as the mouse goes on the lower (1) screen, the mouse coordinates cut, and it seems it tries to fit the (in this case) x-coordinates into the {-1,1} range on that screen too.

My expectation would be, that the main screen (2) sets the scale to have the mouse coords span {-1,1}X/Y on the main screen and the secondary (and other) screens would be treated as a gap-less extension of that main screen (e.g. a second screen, half the size, positioned below the main would make y go up to 1.5)

This bug doesn’t occur when both are the same size. Unaligned screens seem also correctly handled in that case:


Just for convenience - a patch with Mouse (Global) & IOBoxes for X/Y (1.6 kB)