Linux Mint 17.1 I installed the distro’s version of audacity.
Audacity version: 2.0.5
The scrollbars in this version do not have the little buttons to step forward and backward slightly.
I changed my theme so that the GTK config put the steppers on the scrollbars of, for instance, file folders, but they still do not appear in Audacity. Does Audacity use GTK? If so, what version. Does it have its own config file somewhere that I can edit to get the buttons back?
Yes Audacity user wxGTK. If you look at Help > About Audacity… then Build information you can see the wxWidgets version your distro used.
Did a previous version of Audacity have the little buttons? As far as I know, Debian-based versions of Audacity have not had those buttons for some years. Do any wxGTK apps have those little buttons? I suspect not. Filezilla doesn’t. You could raise a report on the Linux Mint bug tracker https://bugs.launchpad.net/linuxmint.
As workarounds you could install WINE then see if the Windows version of Audacity displays the little buttons (it does on Windows). Or, hold SHIFT then scroll the mouse wheel or ball very slightly. This should scroll horizontally as finely as the little buttons do.