I believe "procedure WMVScroll(var Message: TWMVScroll); message WM_VSCROLL;" handles the vertical scrolls.
I am dealing with a massive number of rows (>10^6). I tried it but NextGrid was very slow - which is understandable.
I want to be able to scroll a small subset (100 rows) of the data and handle the refreshes when the user scrolls beyond this subset. In order to do this, I need to be able to intercept the vertical scrollbar events and to position correctly the thumb on scrollbar.
I would much appreciate a tiny example of how to do it.