I mean that when using a stage with stageStyle.UTILITY, I don't want to show the "solid white background " but a transparent background.
I need a stage doesn't shown on the windows' task bar below(stageStyle.UTILITY can satisfy), and I need a transparent background（StageStyle.TRANSPARENT can satisfy）so that I can define the close button style of my stage.
But it seems strange that stageStyle.UTILITY or StageStyle.TRANSPARENT only fit one of my request.
Already OK! Also invoke dialogStage.initOwner(parentStage) http://docs.oracle.com/javafx/2/api/javafx/stage/Stage.html#initOwner%28javafx.stage.Window%29