Google Chrome	72.0.3593.0 (Official Build) dev (64-bit)
Firmware Version	Google_Caroline.7820.384.0

Steps:
# Open Wallpaper app via Settings > Appearance section 
# Attempt to move between sections (citiscapes, landscapes, etc.) using tab or arrow keys
Expected: able to change sections with keyboard
Actual: no way to change sections

# Navigate through the images in a particular section using tab/arrow keys
# Attempt to select one image
Expected: nothing changes until enter or space is pressed
Actual: selection is made automatically after a few seconds 

Please split into two bugs if that is appropriate.