Window.fxml

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.ListView?>
<?import javafx.scene.control.TextArea?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.AnchorPane?>

<AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8.0.111" xmlns:fx="http://javafx.com/fxml/1" fx:controller="chat.app.WindowController">
   <children>
      <TextArea fx:id="outputArea" editable="false" layoutX="42.0" layoutY="43.0" prefHeight="229.0" prefWidth="280.0" />
      <TextField fx:id="inputArea" alignment="TOP_LEFT" layoutX="42.0" layoutY="307.0" onKeyPressed="#ifKeyPressed" prefHeight="55.0" prefWidth="280.0" />
      <Button fx:id="button" layoutX="363.0" layoutY="307.0" mnemonicParsing="false" onAction="#buttonPressed" prefHeight="55.0" prefWidth="156.0" text="Send" />
      <ListView fx:id="userList" layoutX="363.0" layoutY="43.0" prefHeight="229.0" prefWidth="156.0" />
      <Label fx:id="prompt" layoutX="42.0" layoutY="283.0" text="Label" />
   </children>
</AnchorPane>