Не работает setVisible() JavaFX?

Question

de_iiah_teji9_iiace @de_iiah_teji9_iiace

Java
JavaFX

Не работает setVisible() JavaFX?

Есть сцена, на которой комбобокс и гридпейн с кнопками. В гридпейн указан setVisible(false)

<GridPane fx:id="gridPane" layoutX="14.0" layoutY="53.0" prefHeight="233.0" prefWidth="372.0" visible="false">
      <children>
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="4" GridPane.rowIndex="0" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="5" GridPane.rowIndex="0" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="6" GridPane.rowIndex="0" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="0" GridPane.rowIndex="1" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="1" GridPane.rowIndex="1" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="2" GridPane.rowIndex="1" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="3" GridPane.rowIndex="1" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="4" GridPane.rowIndex="1" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="5" GridPane.rowIndex="1" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="6" GridPane.rowIndex="1" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="0" GridPane.rowIndex="2" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="1" GridPane.rowIndex="2" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="2" GridPane.rowIndex="2" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="3" GridPane.rowIndex="2" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="4" GridPane.rowIndex="2" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="5" GridPane.rowIndex="2" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="6" GridPane.rowIndex="2" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="0" GridPane.rowIndex="3" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="1" GridPane.rowIndex="3" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="2" GridPane.rowIndex="3" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="3" GridPane.rowIndex="3" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="4" GridPane.rowIndex="3" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="5" GridPane.rowIndex="3" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="6" GridPane.rowIndex="3" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="0" GridPane.rowIndex="4" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="1" GridPane.rowIndex="4" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="2" GridPane.rowIndex="4" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="3" GridPane.rowIndex="4" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="4" GridPane.rowIndex="4" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="5" GridPane.rowIndex="4" />
        <Button maxHeight="-1.0" maxWidth="-1.0" minHeight="-1.0" minWidth="-1.0" mnemonicParsing="false" text="Button" GridPane.columnIndex="6" GridPane.rowIndex="4" />
      </children>
      <columnConstraints>
        <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
        <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
        <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
        <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
        <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
        <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
        <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
      </columnConstraints>
      <rowConstraints>
        <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
        <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
        <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
        <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
        <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
      </rowConstraints>
    </GridPane>

Вот метод контроллера для комбобокса

@FXML
    private void showDays() {
        if(monthCB == null) throw new IllegalStateException("Error");
        monthCB.setOnAction((event)->{
          String month;
            month = monthCB.getItems().toString();
            if(month == "January")
                gridPane.setVisible(true);
        });
    }

Надо что бы при выборе января появлялся гридпейн.
Может я делаю как то не так, ведь мне кажется, что можно как-то динамически все это создавать, а не менять видимость заранее созданного объекта.
Подскажите плиз что не так в коде, и дайте пару советов как вообще это следует делать правильно.