EventHandler property implementations in Scene and Window use anonymous classes derived from ObjectPropertyBase, for example:

```
public final ObjectProperty<EventHandler<? super MouseEvent>> onMousePressedProperty() {
        if (onMousePressed == null) {
            onMousePressed = new ObjectPropertyBase<>() {

                @Override
                protected void invalidated() {
                    setEventHandler(MouseEvent.MOUSE_PRESSED, get());
                }

                @Override
                public Object getBean() {
                    return Scene.this;
                }

                @Override
                public String getName() {
                    return "onMousePressed";
                }
            };
        }
        return onMousePressed;
```

We can remove lots of boilerplate code by factoring out the implementation into a common class.