I installed a T450 touchpad in my T440, and it works great in Fedora with Kernel 4.0.

However, I found that it is possible to change so holding down the middle touchpad button while pushing the trackpoint facilitates scrolling. By default the middle touchpad button behaves just as a regular mouse’s scroll wheel button, which is not as functional.

Achieving the former behavior on Fedora in X is explained on Thinkwiki. Basically you only have to create the file /etc/X11/xorg.conf.d/20-thinkpad.conf with the following content:

Section "InputClass"
  Identifier    "Trackpoint Wheel Emulation"
  MatchProduct  "TPPS/2 IBM TrackPoint|DualPoint Stick|Synaptics Inc. Composite TouchPad / TrackPoint|ThinkPad USB Keyboard with TrackPoint|USB Trackpoint pointing device|Composite TouchPad / TrackPoint"
  MatchDevicePath   "/dev/input/event*"
  Option        "EmulateWheel"      "true"
  Option        "EmulateWheelButton"    "2"
  Option        "Emulate3Buttons"   "false"
  Option        "XAxisMapping"      "6 7"
  Option        "YAxisMapping"      "4 5"

What is especially great with this solution is that pasting from the X window selection clipboard still works by clicking the middle touchpad button; while holding it down instead triggers the scrolling behavior.

The problem though is that resizing windows in Gnome Shell is, in one way, done by holding down the super key, the scroll button and moving the cursor at the same time. This is shown in the following picture:

Resizing window in Gnome Shell

This obviously collides with the edited middle touchpad button behavior. I explained on ask.fedoraproject.org how one can change the resizing from using the middle mouse button to the right mouse button instead, which then works great on a ThinkPad. To summarize the steps you have to do:

  1. Install Gnome Tweak Tool: $ sudo dnf install gnome-tweak-tool
  2. Open Tweak Tool and go to the page Windows.
  3. Toggle on Resize with Secondary-click.