Keyboard can be scrolled by pressing buttons on either side of it
Keyboard can be scrolled by pressing buttons on either side of it

Previously these buttons were present, but not functional. The
keyboard will continuously scroll as long as the buttons are pressed.

Although this could be implemented by making the keyboard container
scrollable using the `overflow-x: scrollable` CSS style, which would
enable native OS scrolling, this causes problems with determining the
difference between key presses and scroll events.

jstrait/jssynth,jstrait/jssynth