Re: Scrollbar bug on OS X

[Stefan Monnier <monnier@iro.umontreal.ca>]

> I think you are laboring under the delusion that the scroll bar
> actually displays something sensible, namely that mouse-2 exactly at
> the bottom of the slider will take you exactly one page of screen
> material further.  I think you'll find that users are much less
> surprised if this goal is not exactly established than if the slider
> grows and shrinks in size.  So the solution is to base the slider size
> on some more-or-less sensible metric like lines-in-file (where
> available) to lines-on-screen, and anyway, don't muck with it while
> dragging.

That's what the code does with the Motif scrollbar, BTW.
I think it's also what's used with Gtk.


        Stefan


PS: The only problem is that those toolkits have the idiotic idea to enforce
that the bottom of the thumb cannot go further than the bottom.  And they
enforce it by hiding the events corresponding to "user moves the mouse
yet-further-down".  I.e. they're throwing away valuable information before
the application can even decide whether it's indeed useless or not.
It's idiotic because it requires *more* code in the toolkit and has as its
only effect to reduce the flexibility of the toolkit.