title: Make disappear image on the edge of rectangle
body: <p>I have to move some pictures in my flash. So I have got a background image in my main MovieClip(which I get by Loader class). Inside the image I have rectangles. I'm going to put small image in this rectangle and move it.  I need the small image slowly disappear while crossing the rectangle boundaries.
  I tried to put another movieclip in rectangles and moved image in this movieclip. But while crossing the rectangle the image didnt disappear. The image just continued its motion without disappearing.
  How can I make dissapearing of image while crossing rectangle boundaries?
  Sorry for my English.</p>