mouse-event% vs get-mouse-state issues

Following the results gathered from https://racket.discourse.group/t/help-me-gather-keystrokes-and-mouse-events-for-varied-platforms/307/7

On Mac, there are several issues:

• control isn't reported in the mouse-event%, while it is reported by get-mouse-state.

• get-mouse-state reports left button instead of right or middle
  Example of such discrepancies:

  • mouse-event%: right:shift:meta:right-down
    get-mouse-state: (914 602 left shift meta control)
  • mouse-event%: right:right-down
    get-mouse-state: (614 435 left control)

• Some Mac users reported that modifiers are not picked at all with mouse events

On Windows, things are mostly ok except that meta or alt are not always reported in the mouse-event%. Otherwise, the event also reports meta while the state reports alt.
Example:

• mouse-event%: control:shift:left-up
  get-mouse-state: (1878 456 shift control alt)

On Unix, the only issue I found is that the mouse-event% reports meta while the state reports alt.

Unfortunately I don't own a Mac or a Windows machine (only a Linux) so I can't really attempt to debug this. However, one can easily try it out with this:

raco pkg install racket-paint
racket -l- racket-paint/event-listener --mouse-state

Start by running racket -l- racket-paint/event-listener --mouse-state after installing racket-paint, then compare mouse-event% reports with get-mouse-state on Mac, Windows, and Unix. Investigate the platform-specific modifier and mouse-button discrepancies described in the issue; done means the two APIs report consistent state across the tested platforms.