JavaFX TextArea does not append text properly - javafx

Question

I'm trying to build a simple calculator using TDD, so I have a TextArea that is right aligned to display the results and 20 buttons. Everytime one of the digit buttons are pressed it just appends the digit to the TextArea, the same thing was supposed to happen when I press the dot button. But instead it places the dot as the first character in the TextArea, only when I press a new digit the dot goes to its proper place.
So for example, if I press 9 and then 8 the TextArea shows "98", now if the dot is pressed the result will be ".98", finally if 7 is pressed the result is "98.7".
The expected result when I pressed the dot button should have been "98.".
I created a Minimal, Complete, and Verifiable example bellow
FXMLDocument.fxml:
<AnchorPane id="AnchorPane" prefHeight="175.0" prefWidth="256.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/8.0.141" fx:controller="mcv.FXMLDocumentController">
<children>
<Button fx:id="buttonNine" layoutX="14.0" layoutY="100.0" onAction="#handleButtonNine" prefHeight="60.0" prefWidth="69.0" text="9">
<font>
<Font size="24.0" />
</font></Button>
<TextArea fx:id="textArea" editable="false" focusTraversable="false" layoutX="15.0" layoutY="14.0" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" nodeOrientation="RIGHT_TO_LEFT" prefHeight="66.0" prefWidth="221.0" wrapText="true">
<font>
<Font size="35.0" />
</font>
</TextArea>
<Button fx:id="buttonDot" layoutX="169.0" layoutY="100.0" mnemonicParsing="false" onAction="#handleButtonDot" prefHeight="60.0" prefWidth="69.0" text=".">
<font>
<Font size="24.0" />
</font>
</Button>
</children>
</AnchorPane>
FXMLDocumentController.java:
#FXML
private TextArea textArea;
#Override
public void initialize(URL location, ResourceBundle resources) {
}
private void appenToResult(String ch){
textArea.appendText(ch);
}
#FXML
void handleButtonDot(ActionEvent event) {
appenToResult(".");
}
#FXML
void handleButtonNine(ActionEvent event) {
appenToResult("9");
}
As you can see the code is very simple. It should be working, my only clue is that this is a bug with the TextArea when the Node Orientation is set to RIGHT_TO_LEFT. If node orientation is set to INHERIT or LEFT_TO_RIGHT it works as expected. Thank you.