The scroll bar arrows seem to have disappeared from everything except Firefox after a recent update of Ubuntu 15.10. I have poor hand-eye coordination, and am having a very hard time adjusting to OSX-style arrow-less scroll bars. Is there a way of getting scroll bar arrows back, short of switching to a different window manager? I'm so frustrated that I'm actually starting to miss CDE on Solaris.
You need a theme for GTK that doesn't have those overlay scroll bars. Most pre-15.10 themes should work, for example Irradiance.
You need to use Unity Tweak Tool, Unsettings or a similar tool to select the theme as the official Unity settings only deal with themes for the current version of Unity.