Why can't the mouse move the cursor in the air? But you can still click.

The mouse gets the information of mouse movement through the rubber ball or LED at the bottom.

Rubber ball, after leaving the desktop, can't scroll, naturally can't move the cursor.

Photoelectricity is because the light emitted by light-emitting diodes is converted into electrical signals by optical sensors and reflected on the mouse to realize the movement of the cursor. This transmission and reception must be within a certain distance from the reflecting object. So you can't move when you leave the desktop.

Clicking is purely mechanical. When you click, you directly press the button inside the mouse and convert it into an electrical signal to realize the clicking behavior, regardless of the position of the mouse.