If you put a grid in the middle of long page,
When you scroll with the mouse wheel,
It stop over your grid, and begin to scroll in the grid, cool
but when it arrive at the end or when there's no scroll in the grid
we have to move out the mouse off the grid to continus to scroll.
The best behaviour will be
When there no scroll in the grid or the scroll in it are at the end,
give back the scroll action to the main window
Or a plan B
It there a way to desable the scroll wheel action in your grid.