I've used GetScrollInfo a few times but I don't know what you mean by 'scroll bars disappear'.
Here's the scenario,
1. User scrolls the control to the last collumn.
2. User then chooses to stretch window to see all grid.
3. Scroll bars go away because the window size is greater than the page size.
Unfortunately the window might not be aligned with the Grid.
At this point I want to pan the view so that the top left of the grid is the top left of the control but unfortunately GetScrollInfo() returns an empty structure.
The solution was to store the scroll info independent of the Control's window.