When I try to get screensize like this:
        Rectangle2D primaryScreenBounds = Screen.getPrimary().getVisualBounds();
        double w = primaryScreenBounds.getWidth();
        double h = primaryScreenBounds.getHeight();
        double xMax = primaryScreenBounds.getMaxX();
        double yMax = primaryScreenBounds.getMaxY();
I get that:
w = 1440.0
h = 874.0
xMax = 1440.0
yMax = 896.0
But my screen on the MacBook Pro is 1440x900 px! I check it.
So, where is my 4 pixels from yMax?