And met his friend the same question, and touchpad mouse left button (touchpad is a "click" action), fail, become a double-click.
This friend wrote:
The left button of the mouse suddenly does not work, the touch version is useless, the right button is available.
Reason: Two Bluetooth mice are turned on at the same time and connected to the mac, a mouse is placed in the bag and a button is pressed, and the computer is connected If the mouse in the bag is removed, the mouse on the desk cannot be used and the touchpad is not fully functional.
Turn off a Bluetooth mouse to return to normal.
But I did not use a Bluetooth mouse, but a Logitech receiver directly. So rule out the reason he found. But it did point me to the direction. It turned out that the reason for my failure was that the Bluetooth keyboard was put in the bag and was pressed (some keys), which caused the problem.
At this point, the problem is solved.
reference: