Im am using Elementary OS on a laptop and clicking in the middle of the trackpad's buttons would trigger a middle click. I would like to disable that.
Running the following command in the terminal could solve this:
xmodmap -e "pointer = 1 25 3 4 5 6 7 8 9"
To make this persistent, edit your ~/.Xmodmap with a text editor either from the terminal:
or with a graphical text editor:
open files --> go to your home directory --> open .Xmodmap (a hidden file) with a right click in "Scratch" or another text editor. If the file doesn't exist, create a new file with the name .Xmodmap
and add this line
pointer = 1 25 3 4 5 6 7 8 9