Whilst the BANano object has a UseCapture variable on removeEventListener, the BANanoObject does not. If you added an event on the BANanoObject directly with a true UseCapture, when executing removeEventListener, what are the implications of the missing useCapture? I understand that this by default is False.
I'll add the parameter in the RemoveEventListener. In almost all cases you want to use bubbling so that is why I omitted it (not in AddEventListener, but that was more to avoid the modern browsers from giving a warning).
Capturing vs Bubbling:
With capturing, the event is first captured by the outermost element and propagated to the inner elements.
With bubbling, the event is first captured and handled by the innermost element and then propagated to outer elements.