Listener mousemove event on Graphics element

Hello everyone!

I'm trying Pixi.js for a week and still, I don't understand what's going on with the PIXI.Graphics() class.

I want to drag my graphic circle but from the following code, I get that the 'mousemove' event is triggered when I move the mouse cursor on my canvas, not only on my graphic circle.

    elem = new PIXI.Graphics();
    elem.beginFill(0xFFFFFF);
    elem.drawCircle(50, 50, 10);
    elem.endFill();

    myStage.addChild(elem);

    elem.on('mousemove', (e) => { console.log(e); });

What am I missing?

Since I am experimenting with the interaction between pixi canvas and user input, are there any guides to understanding better what's happening under the hood and how to correctly manage it?