how to re-position the child nodes when the screen size is increased - javafx-8

Question

I have an anchor panel wrapped in a Border panel (anchor panel positioned at the top ) .Anchor panel has a Menu bar to the top left and set of buttons aligned to the top right of the anchor panel. When is maximize the screen to full screen the buttons do not hold the position according to the increased screen size. I there a way to set the button co-ordinates relatively to the parent size ?
here is the code of the anchor panel.
<AnchorPane xmlns="http://javafx.com/javafx/8.0.65" xmlns:fx="http://javafx.com/fxml/1"
fx:controller="application.views.MenuControls">
<children>
<MenuBar prefHeight="20.0" prefWidth="181.0">
<menus>
<Menu mnemonicParsing="false" text="First Menu">
<items>
<MenuItem fx:id="displayOne" mnemonicParsing="false"
onAction="#switchToOne" text="Display Anchor Pane One" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Second Menu">
<items>
<MenuItem fx:id="displayTwo" mnemonicParsing="false"
onAction="#switchToTwo" text="Display Anchor Pane Two" />
</items>
</Menu>
</menus>
</MenuBar>
<Button layoutX="590.0" mnemonicParsing="false" prefHeight="15.0" text="Close"
prefWidth="30.0" onAction="#closeApplication" managed="true" >
<!-- <graphic>
<ImageView fitHeight="17.0" fitWidth="17.0" layoutX="539.0"
layoutY="4.0">
<Image url="#close.png" />
</ImageView>
</graphic> -->
</Button>
<Button layoutX="560.0" mnemonicParsing="false" prefHeight="15.0"
prefWidth="30.0" onAction="#minimizeApplication" text="Min" managed="true">
<!-- <graphic>
<ImageView fitHeight="17.0" fitWidth="17.0" layoutX="577.0"
layoutY="4.0">
<Image url="#close.png" />
</ImageView>
</graphic> -->
</Button>
<Button layoutX="530.0" mnemonicParsing="false" prefHeight="15.0"
prefWidth="30.0" onAction="#maximizeApplication" text="Max" managed="true">
<!-- <graphic>
<ImageView fitHeight="15.0" fitWidth="17.0" >
<Image url="#close.png" />
</ImageView>
</graphic> -->
</Button>
</children>
</AnchorPane>