It seems like the unity DE somehow blocks the mouse gesture for itself, thus most of the other multi-touch recognizers can not catch the events.

To disable this, the unity multi-touch support need to be completely disabled:

1. Install dconf-editor, using apt install dconf-editor -y.
2. Launch dconf-editor via command line.
3. Go to com->canonical->unity->gestures and disable everything inside.

Now tools like toughegg could catch touchpad events as normal.

2017/11/23