Thanks for the reply, OSUBlake.
I'm trying to solve the issue after dropping the tile on the board (apologies.. my original post was vague on this point). So sequence is:
drag tile from rack onto board;
drop tile on board;
then drag to new position on board
The issues I'm trying to resolve are with point 3. At that point, when I drag an item, the auto scroll doesn't behave as expected. And when dragging to the edge of the container, the container continuously grows.
Thanks again for the help.