Comment 7 for bug 1439948

Since upgrading to Xubuntu 15.10, neither vertical nor horizontal scrolling work with this keyboard.

ID is now 21:

gdi2k@x250:~$ xinput list
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ TPPS/2 IBM TrackPoint id=13 [slave pointer (2)]
⎜ ↳ Razer Razer DeathStalker id=15 [slave pointer (2)]
⎜ ↳ Razer Razer DeathStalker id=16 [slave pointer (2)]
⎜ ↳ Logitech M705 id=18 [slave pointer (2)]
⎜ ↳ Lenovo ThinkPad Compact USB Keyboard with TrackPoint id=21 [slave pointer (2)]
⎜ ↳ SynPS/2 Synaptics TouchPad id=10 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
    ↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
    ↳ Power Button id=6 [slave keyboard (3)]
    ↳ Video Bus id=7 [slave keyboard (3)]
    ↳ Sleep Button id=8 [slave keyboard (3)]
    ↳ AT Translated Set 2 keyboard id=9 [slave keyboard (3)]
    ↳ ThinkPad Extra Buttons id=11 [slave keyboard (3)]
    ↳ Integrated Camera id=12 [slave keyboard (3)]
    ↳ Razer Razer DeathStalker id=14 [slave keyboard (3)]
    ↳ C-Media USB Audio Device id=17 [slave keyboard (3)]
    ↳ UVC Camera (046d:0821) id=19 [slave keyboard (3)]
    ↳ Lenovo ThinkPad Compact USB Keyboard with TrackPoint id=20 [slave keyboard (3)]

gdi2k@x250:~$ xinput list-props 21
Device 'Lenovo ThinkPad Compact USB Keyboard with TrackPoint':
 Device Enabled (139): 1
 Coordinate Transformation Matrix (141): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
 Device Accel Profile (263): 0
 Device Accel Constant Deceleration (264): 1.000000
 Device Accel Adaptive Deceleration (265): 1.000000
 Device Accel Velocity Scaling (266): 10.000000
 Device Product ID (257): 6127, 24647
 Device Node (258): "/dev/input/event23"
 Evdev Axis Inversion (370): 0, 0
 Evdev Axes Swap (372): 0
 Axis Labels (373): "Rel X" (149), "Rel Y" (150), "Rel Horiz Wheel" (582), "Rel Vert Wheel" (583)
 Button Labels (374): "Button Left" (142), "Button Middle" (143), "Button Right" (144), "Button Wheel Up" (145), "Button Wheel Down" (146), "Button Horiz Wheel Left" (147), "Button Horiz Wheel Right" (148), "Button Side" (709), "Button Extra" (710), "Button Unknown" (369), "Button Unknown" (369), "Button Unknown" (369), "Button Unknown" (369)
 Evdev Scrolling Distance (375): 1, 1, 1
 Evdev Middle Button Emulation (376): 1
 Evdev Middle Button Timeout (377): 50
 Evdev Third Button Emulation (378): 0
 Evdev Third Button Emulation Timeout (379): 1000
 Evdev Third Button Emulation Button (380): 3
 Evdev Third Button Emulation Threshold (381): 20
 Evdev Wheel Emulation (382): 1
 Evdev Wheel Emulation Axes (383): 6, 7, 4, 5
 Evdev Wheel Emulation Inertia (384): 10
 Evdev Wheel Emulation Timeout (385): 200
 Evdev Wheel Emulation Button (386): 2
 Evdev Drag Lock Buttons (387): 0

I will try your xorg.conf to see if it improves things.

This keyboard is attached to a Lenovo X250 laptop, and the trackpoint on the laptop works fine (including vertical and horizontal scrolling).