Fontsize changed in settings won't trigger editorex.addPropertyChangeListener

Hi, I'm using this code to get notified when user has changed fontsize and it works well with shot-cut event. But after I changed fontsize in Settings - Editor -Font, it won't trigger the listener. Any Ideas about this? Thank you very much for help!     
 editorex.addPropertyChangeListener( evt -> {
            if (EditorEx.PROP_FONT_SIZE.equals(evt.getPropertyName())) {
                // Handle font size change here
            }
        }, editorDisposable);