Comment 39 for bug 1758306

@leonciomaya

This issue was definitely fixed so you there is likely something else going on with your system. Here are some suggestions:

Check all updates are installed? Try proposed updates?
Is this with mouse or trackpad?
Have you checked what gsettings is reporting?

    gsettings get org.gnome.desktop.peripherals.mouse left-handed

Perhaps try a booting with a livecd ubuntu and test mouse there.

I will also say that it can be assumed that everyone including the OP consider this specific issue fixed (I am muting this bug). Therefore you will need to open a new launchpad bug. You can also use the ubuntu forums or IRC for direct help with diagnosing the issue.