How to set / delete insets in JavaFX titledpane

I created a titledpane with a single sub component (button) in JavaFX, as follows:

<?import java.lang.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1">
    <children>
        <TitledPane animated="false" layoutX="137.0" layoutY="60.0" prefHeight="400.0" prefWidth="600.0" text="untitled" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
            <content>
                <AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="180.0" prefWidth="200.0" >
                    <children >
                        <Button layoutX="193.1875" layoutY="133.5" mnemonicParsing="false" prefHeight="374.0" prefWidth="598.0" text="Button" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0" />
                    </children>
                </AnchorPane>
            </content>
        </TitledPane>
    </children>
</AnchorPane>

As shown below There is quite a lot of space around the button. I want to reduce it to 0 or maybe a single pixel I don't see any properties of anchorpane or titledpane that can perform this operation Do you have such property?

Solution

Use scene view to find out such problems

The anchorpane inside the titledpane is filled with 0.8em (10px) on all sides This is in the default style sheet Modena Defined in CSS You can reset it in fxml:

<?import java.lang.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<?import javafx.geometry.Insets?>

<AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1">
    <children>
        <TitledPane animated="false" text="untitled" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
            <content>
                <AnchorPane >
                <padding>
                        <Insets top="0" right="0" left="0" bottom="0"/>                 
                </padding>
                    <children >
                        <Button mnemonicParsing="false" text="Button" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0" />
                    </children>
                </AnchorPane>
            </content>
        </TitledPane>
    </children>
</AnchorPane>

Or with an external style sheet

.titled-pane > * > * > AnchorPane {
    -fx-padding: 0em ;
}