The scrollbars in LibreOffice are missing the arrows at either end of the scroll. I have added the settings in ~/.config/gtk-2.0/gtkrc and ~/.config/gtk-3.0/gtk.css that shoudd theoretically enable them, but the scrollbars are still devoid of the necessary arrows.
I am presuming LibreOffice 5.0x is still running GTK2, since GTK3 apps seem to be correctly displaying scrollbar arrows.
Linux, English
Writer, Calc, presumably all other components
There was a concerted effort to port LO v5.x to GTK3 however the work is not yet complete. There is a presentation on the work in this Phoronix blog post which offers technical details.
This may not be a very helpful answer, but if you logged in and selected some desktop that wasn’t running GTK3, you’d be fine. I’m using Ubuntu 16.04 Compiz I think (using the options that avoids the Unity UI), and it’s working fine.
Try to start on a terminal window the command "SAL_USE_VCLPLUGIN=gen libreoffice ". If it shows the scrollbars arrows the uninstall libreoffice-gtk2 and libreoffice-gtk3. This solved it by me.