To resolve this issue, I took the approach of extending the ComboBoxListViewSkin. Within this extension, I implemented a method that is responsible for updating the styling. This method works by first invoking super.getPopup() to retrieve the AnchorY value, which is then compared to the Y value of the combo-box. Based on whether the popup is positioned above or below the combo-box, the appropriate styling is applied to super.getListView...
Furthermore, it is crucial that this method is called during the "ON_SHOWN" event of the combo-box.
I experimented with various alternatives, but unfortunately, they all resulted in unpredictable behavior.