I was reading the documentation of Qt example of ["scribble"](http://doc.qt.digia.com/4.6/widgets-scribble.html). There I stumbled across the following piece of code:

```
 void ScribbleArea::mouseMoveEvent(QMouseEvent *event)
 {
     if ((event->buttons() & Qt::LeftButton) && scribbling)
         drawLineTo(event->pos());
 }

 void ScribbleArea::mouseReleaseEvent(QMouseEvent *event)
 {
     if (event->button() == Qt::LeftButton && scribbling) {
         drawLineTo(event->pos());
         scribbling = false;
     }
 }

```

One question arised in my mind on whether there's actually any difference between `event->button() == Qt::LeftButton` and `(event->buttons() & Qt::LeftButton)`. Could you please explain? Thanks.