ControlsFx notification adds padding into application

Question

This is the image from my system before call ControlsFx notification

This is the image from my system after call ControlsFx notification

It adds a border in the left, right top and bottom of the screen. I have already searched the documentation but there's nothing talking about the mistake.

This is my code:

Notifications.create()
                .title(title)
                .graphic(ImageView(Image("/image/error_icon_little.png")))
                .text(text)
                .position(Pos.TOP_RIGHT)
                .hideAfter(Duration.seconds(4.0))
                .show()