on my win10 laptop there is a single pixel under the taskbar that prevents me from moving my mouse all the way down when trying to switch to different window (i use small taskbar icons with enabled labels so they're supposed to be easy to select with little precision). it just doesn't click them; i have to move my mouse up a little.
note: this actually is using a mouse
i just fixed it by toggling auto hide taskbar on and off XDD
let's see if it caries over after restart...
update: it does not