Class recasting movieclip as displayobject

Hi All

I’ve tried googling for this situation and can’t find anything that addresses this specifically.

I have a class linked to a movieClip in a library. The MVC class (linked to the movieclip and entending the MovieClip class) instantiates the Model, View, and Control classes and passes them _gallery = this as MovieClip.

In each of the subclasses the _gallery is reassigned to _currentGallery as MovieClip.

In the View Class, the function that builds the menu accepts the _currentGallery as a MovieClip, but in a later function when I try _currentGallery.getChlldByName(“page0”) it returns "1061: Call to a possibly undefined method getChildByName through a reference with static type flash.display:DisplayObject.

I can force it to behave by recasting as MovieClip, but I don’t understand why it’s recasting itself as a display object or how to prevent it.

Thanks in advance for any links, basic principles, formatting advice, or other helpful information you can give this lost newb