Sometimes we wanna disable middle click, for example, middle click in Firefox will open link in a new tab, and it is difficult to disable it in Firefox.
We can use xmodmap to disable middle click:
xmodmap -e "pointer = 1 0 3"
There is a bug of xmodmap 1.0.3 on Slackware 13.0, the above command won't work. It will report "xmodmap: commandline:1: bad value 0 given for buttons list".
xmodmap 1.0.4 on Slackware 13.1 works well.