Discover 5.9.3-1.1 with Plasma 5.9.2 on openSUSE Tumbleweed. I use a touchpad with two-finger scrolling. Discover does not utilize this feature, and doing a two-finger scroll does not scroll pixel-by-pixel like it should; instead, it scrolls many lines at a time.
Forgot to mention that I'm using xf86-input-synaptics, not libinput.
*** This bug has been marked as a duplicate of bug 376910 ***