Resizing ComboBox by scaling screen size

I'd like to make my application resizable. I want to resize all child elements and its font size and images depending on the height and width.

I followed the instructions on the following page: Bond Font Size and Image with Thresholds. The answer contains two approaches. The first approach works fine but the second approach does not resize the ComboBox elements. What do I need to change to make the second approach work for dropdown of ComboBoxes as well?

Example code is given here Bond Font Size and Image with Thresholds as well.

Try to access the scale attribute from LetterBoxer and set that scale to listView of the ComboBox while showing.

selectCardReaderCombo.setOnShowing(e->{
    selectCardReaderCombo.getChildrenUnmodifiable().stream()
            .filter(n-> n.getStyleClass().contains("list-view"))
            .forEach(n->{
                n.getTransforms().setAll(boxSizeAdjuster.scale);
    });
});