Losing left mouse click after awhile

Machine in question is an old Acer Aspire One ZG5 (netbook), and I seem to be encountering a bizarre issue. After the machine idles for a bit while playing internet radio via Clementine, I lose the ability to left mouse click. Pointer moves about normally, and right clicking works. It’s not the mouse (cheapo wireless USB), since whenever this happens I also lose the left click on the track pad. I tested with a wireless USB Logitec keyboard + trackpad, same deal; left click eventually stops working.

Any clues on how to tackle this?