Re: [MACTCL] Weird behaviour of Mac scrollbar

[Kevin W. <kw...@co...>]

Hi Torsten,

On 3/30/17 5:22 AM, Torsten Berg wrote:
> since quite some time I am experiencing a weird behaviour of the Tk scrollbar on the Mac. E.g. when I have a listbox (but this applies to all other widgets as well) and vertically scroll through it using the slider of the scrollbar, I need to click and hold the slider on the lower end in order to be able to move it. I can also click and hold below the slider, in the open space of the trough, it still moves. However, when I click on the upper part of the slider, the behaviour is as if I had clicked into the trough above the slider.
> It seems as if the position where the mouse click occurs is not in sync with where the slider actually is.

I've seen this behavior, the slightly jumpy behavior of the scroller in 
some situations, and I'm sure it's the result of the various changes I 
committed; the changes to the scrollbar were my work. I am not certain 
of how to address it. The redesign of the scrollbar essentially involved 
rewriting the C-level code to remove all the Cocoa scrolling management, 
which had all kinds of hidden issues, and use HITheme to draw the 
scrollbar only, and delegate scrolling behavior to the Unix scripting 
bindings. It's possible that there is a slight mismatch there somewhere, 
but I do not know where to find it. Getting the scrollbar working took a 
couple of months of work on my part--I quit when it was Basically Good 
Enough--and I do not have that kind of time these days to re-investigate 
it. Anyone else is welcome to take a look and I'll gladly review patches 
that take it to higher level.

--Kevin

-- 
Kevin Walzer
Code by Kevin/Mobile Code by Kevin
http://www.codebykevin.com
http://www.wtmobilesoftware.com