Photon takes over the PC mouse!

I have had this happen several times, even with the simplest programs:

void setup() {

void loop() {

When the photon starts running, the PC mouse jumps in small amounts up and to the left, and I have no control.

If I disconnect the photon, I regain mouse movement control, but the mouse will no respond to clicks until I
cotl-alt-delete and the cancel.

@rcomeau, a quick search in the Community for “mouse” turns up: