> When I enable the toolkit (in this case, gtk3) scroll bar, there is an
> extra pixel line at scroll bar's right. With dark backgrounds, this
> problem is more obvious. I've uploaded an image here,
> http://i.imgur.com/vfThig4.jpg, as you can see, the scroll bar's
> backgound is bright, and there is an extra dark line at it's right. This
> line is absolutely of no use and in my opinion, it's very ugly.
>
>
>
> In GNU Emacs 24.3.92.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8)
> of 2014-07-10 on gentoo
> Windowing system distributor `The X.Org Foundation', version 11.0.11500000
> System Description: NAME=Gentoo
This might be related to the rounding in update_theme_scrollbar_width of
gtkutil.c. Can you try to remove the line
if (w < 16) w = 16;
there and see whether the problem persists? Alternatively, you could
try to increase the slider-width of your Gtk scrollbars
martin