#3088 MouseWheel on Mac : wrong x y

[Aldo Buratti]

I noticed this strange behaviour on Mac (on Win it's OK):
I'm working with ActiveTcl 8.5.13

Let's take this simple case
canvas .c -bg yellow
pack .c -expand true -fill both -pady 50 -padx 50
focus .c ;# this is necessary on Windows ..
#
bind .c <Button-1> { puts "B1 on %W %x %y" }
bind .c <MouseWheel> { puts "MW on %W %x %y" }

* On Windows
Acting on B1 and on MouseWheel, you get the same coords (GOOD)
* On MacOs
Printed coords are different ! In particular if you click near the top-left corner you'll get something very close to (0,0) (good), but if you act on mousewheel you'll get something close to (50,50) !!