You may use this method to determine whether the event box should be
above or below the window of its child. If the window is above,
then all events inside the event box will go to the event box itself.
However, if the window is below, events in the event boxes'
children will first go to that widget, and then to the parent.
The default option keeps the window below the child.
The function will return true if the window is
above the child, false otherwise.