Keeping a clip inside of another

I have a movie clip that has nothing but a border without any fill and has text inside of it. When you rollover the text, it attaches a movie clip from the library and follows the mouse for as long as your over the text. My question is, sometimes, the attachees are too big and run off of the stage so does anyone know of a method that I can use that will keep the attachees within the border of the movie clip in which it is contained in?

I tried using hitTest, but hitTest shows as true all the time. Can’t have this. Any help would be appreciated. Thanks!