Can I remove the carrot (upside down triangle) the CombBoxListViewSkin adds to ComboBox Control?

How can I remove the carrot' (upside down triangle) created by the ComboBoxListViewSkin? Or where I go to find out how to resolve this?

I'm using the CombBoxListViewSkin's class popup listener to prevent the [SPACE] from selecting and closing the ComboBox and allows the [SPACE] character to be typed. When implemented, this adds a 'carrot' to the ComboBox which is not aesthetically appealing in the application GUI. It can leave the user with the impression there is an issue with this part of the application compared with other ComboBoxes and parts of the application.

ComboBoxListViewSkin cbSkin = new ComboBoxListViewSkin(myComboBox);
cbSkin.getPopupContent().addEventFilter(KeyEvent.KEY_PRESSED, (event) -> {
    if(event.getCode() == KeyCode.SPACE){
        filter += " ";
        event.consume();}
});