I'm running Debian Jessie.
$ gnome-session --version
gnome-session 3.14.0
$ dpkg -s libgtk-3-0 | grep '^Version'
Version: 3.14.5-1
I can restore the scroll bar arrows by doing:
Applications->System Tools->Tweak Tool
In Appearance, change GTK+ to HighContrast vs. Adwaita (default)
But where do these changes get saved ?