William Morder composed on 2018-05-14 06:47 (UTC-0700):
Which distro?
Which Xorg version?
Which input driver version(s)?
What is mouse age, brand and model?
Is the mouse plugged into an extension cable? If yes, does removing or replacing the extension help?
Is the mouse cable parallel to one or more other cables that can be relocated?
Does the mouse use batteries and need either new ones or contacts cleaned?
Have you tried unplugging mouse and plugging it back in?
Have you tried moving the mouse cable or antenna to another port?
Have you tried purging *mouse* driver and leaving it up to *input* driver to handle the mouse?