Left/Right cursor buttons to scroll the most-central boosts-pane

**Is your feature request related to a problem? Please describe.**
I sometimes read at my standing-desk while brushing my teeth which leaves me with only one hand. Mouse-clicking the tiny side-buttons to scroll the boosts-pane sideways can be perilous due to the vibrations from the electronic toothbrush, and anyway, my fingers aren't on the mouse they're on the cursor keys.

**Describe the solution you'd like**
When I press left or right on the cursor keys I'd like the middlemost boost pane to scroll left or right accordingly.

**Describe alternatives you've considered**
Currently I have to keep moving to the mouse and clicking the side-buttons. I also try clicking the side-button and then pressing tab, which moves focus into the pane and then does allow left/right to work, but it'd be cooler if I didn't have to touch the mouse.

**Additional context**
I suppose disabled people who only have one hand might benefit as well as those who are merely diverting their attention while brushing teeth.