martin rudalics wrote:

> We first have to make sure that you indeed click on the stepper
> buttons.  For this purpose please do the following with Emacs -Q:
> Evaluate
> 
> M-: (setq window-min-height 1) RET
> C-x 2
> M-: (window-resize nil (- 2 (window-height))) RET
> 
> This should get you a one-line window on top of the frame.  Here this
> window has just two small stepper buttons and no slider.  Hopefully,
> yours is the same.

Unfortunately, not.  I initially get whitespace where the scrollbar
should be.  If I change the theme a few times, I eventually get stepper
buttons, but the slider is included, and it all extends down into the
second window (see attached).  (This is with the emacs-26 branch, built
July 4.)

> Now please tell us what clicking or pressing such a button produces.
> If running this under GDB reveals that in xg_scroll_callback 'scroll'
> equals GTK_SCROLL_JUMP, then please tell us the values of 'whole' and
> 'value' in that case.

I've attached 2 logs from the gdb session.  The first was after using
your original instructions.  The second was from using (- 3 ...) instead
of (- 2 ...).  (In the second case the scrollbar was visible, but again
it extended into the lower window.)

Let me know if I messed something up or there is additional data you
need.

thanks,
mike