Can't scroll using the arrow keys

[peterwvj]

Fine-grained scrolling using the UP and DOWN keys doesn't work. The following message is shown:

Scrolling using the mouse-wheel, on the other hand, works fine. I'm using the following SNAPSHOT version of Emacs.

GNU Emacs 26.0.50.2 (x86_64-pc-linux-gnu, GTK+ Version 3.18.9) of 2016-10-26