Middle mouse emulation
From WikiDotMako
If you use a keyboard like a Unicomp Endura you might find yourself without a middle mouse button. Fortunately, you can press the left and right buttons together to emulate the behavior of pressing a middle mouse button, but only if you create or edit your xorg.conf in /ect/X11 and add the following entry:
Section "InputClass"
Identifier "middle button emulation class"
MatchIsPointer "on"
Option "Emulate3Buttons" "on"
Option "MiddleEmulation" "on"
EndSection
