Comment 58 for bug 1590590

ok,
after further googling it turned out these up-right and bottom-right top shortcuts for middle and right button are default in Ubuntu (and not specific of our trackpad).
So the new driver is working as expected.

For those finding very annoying the accidental middle button click when tapping the up-right part of the trackpad there is a workaround to disable it using the synclient command:

synclient RTCornerButton=0 ! disable up-right middle click
synclient RBCornerButton=0 ! disable bottom-right right click

You can also put the above commands in the "startup applications preferences" control panel to make them persistent after a reboot