- a click near the middle of the screen activates a button in the launcher on the left side
- occasional hits on the exit button of a window, though the cursor was far from it
- inability to drag to select text; the selection would jump upward while I was trying to drag down
- other dragging operations would create unpredictable and unwanted results
I did research and found these two references:
http://askubuntu.com/questions/202789/cursor-jumps-when-moving-and-some-other-times
https://forums.virtualbox.org/viewtopic.php?f=3&t=51727&start=45
Based on these, I typed the following into the terminal.
sudo apt-add-repository ppa:a7x/bug1041063
sudo apt-get update
sudo apt-get install xserver-xorg-core
My initial tests show this to be a successful fix for the problems listed above.