I have a Dell 6320, with both a touchpad and dual stick (you know, the little nipple in midst of the keyboard).
For some strange reason the Alt+middle button resizing of a window stopped working on my Ubuntu installation in the latest Ubuntu version (LTS 12.04). This is a great disadvantage for me, so I did some research.
Re-enable the HW middle button with a terminal
Open up a terminal, and type this:
xinput set-int-prop "DualPoint Stick" "Evdev Middle Button Emulation" 8 0 xinput set-int-prop "DualPoint Stick" "Evdev Wheel Emulation" 0
These settings will reset when you boot, so to make this permanent for the entire system, make your /usr/share/X11/xorg.conf.d/11-evdev-trackpoint.conf file to look like this :
# file: /usr/share/X11/xorg.conf.d/11-evdev-trackpoint.conf # Trackpoint users want wheel emulation. # Yes, but not DualPoint Stick users! ;) /guzaho Section "InputClass" Identifier "trackpoint catchall" MatchIsPointer "true" MatchProduct "TrackPoint|DualPoint Stick" MatchDevicePath "/dev/input/event*" Option "Emulate3Buttons" "false" Option "EmulateWheel" "false" Option "EmulateWheelButton" "2" Option "XAxisMapping" "6 7" Option "YAxisMapping" "4 5" EndSection
Re-enable the HW middle button with GUI
If you prefer, you can install and run the gpointing-device-settings app. In a terminal, type this:
sudo apt-get install gpointing-device-settings gpointing-device-settings
Now uncheck the «Use middle button emulation» and «Use wheel emulation» checkboxes under DualPoint Stick.
The DualStick comes with 3 hardware buttons, but the DualStick config has the Three button Emulation turned to «true». This means that you’re telling your Xserver that your DualStick does NOT have a third button, and that it should enable faking the third button behaviour when you press both of the left and right buttons simultaneously.