Animated scrollpane works one way only?

Hi,
I’ve got a movie on my stage and that also contains a movie, which contains a scroll pane, I have a button that slides the original movie onto the visible stage, and another button that then removes it…

The scrollpane slides on containing a movie just fine but then when it slides off, the scrollbar remains… I can’t see any reason for this as the rest of the movie moves and even the items on the same layer as it move.

Very puzzling. Any ideas?