How to fix GTK3 scrollbar behavior
Solution 1:
Found the answer here:
https://forums.gentoo.org/viewtopic-t-948904-start-0.html
Edit (or create) the file:
~/.config/gtk-3.0/settings.ini
And add the following:
[Settings]
gtk-primary-button-warps-slider = false
Solution 2:
For GTK2 applications, I also noticed the scrollbar-warp behavior happens with the Adwaita theme (but not with the Greybird theme). I fixed it for GTK2 by editing /usr/share/themes/Adwaita/gtk-2.0/gtkrc
and changing the line
gtk-primary-button-warps-slider = 1
to
gtk-primary-button-warps-slider = 0
Solution 3:
The behavior appears tied to the desktop theme/style you select. If you install the gtk2-engines-xfce
package and then select one of the GTK2 themes (e.g. Xfce-4.0) from the Appearance settings, you will get GTK2-style scroll bars.
Unless you are particularly interested in using Adwaita or Greybird, I think the best (and certainly easiest) solution is just to pick a different theme.