Here is a possibly related observation:
- open Squeak on a high-DPI screen (so that everything will look tiny unless you change the image-side scale factor) - move the window to a low-DPI screen - now all mouse cursor looks very tiny. The image-side rendered cursor (as can be seen when dragging a morph) looks correct, though.
This effect occurs the other way around, too, when starting the window on a low-DPI screen and moving it to a high-DPI screen. Maybe the cursors should always be rendered with respect to the operating system's scale factor?