I have the exact same problem here. I have a DELL XPS 14z. I first thought it was an hardware problem and I'm glad to see it isn't. I didn't think about the charger at first but it is now obviously related. It stops shaking on battery. Here my `/var/log/Xorg.0.log`.
** Attachment added: "Content of `/var/log/Xorg.0.log`" https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/1028617/+attachment/3658694/+files/Xorg.0.log -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-input-synaptics in Ubuntu. https://bugs.launchpad.net/bugs/1028617 Title: Cursor shakes violently when connected to power source - makes touchpad cursor unusable To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/1028617/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp