Hi, Boki:
Hope you are well.
This issue has been a problem ever since NextGrid6 was introduced. I used to get around it in NextGrid5 by catching the Row being < 0 in the OnVerticalScroll event. But that does not work any longer.
This happens pretty much all the time when scrolling up using the scroll bar of the grid.
My fix was to change your code, which I really do not like to do. So could you either provide an alternative or change your own code?
see:
TNxListGridView6.ScrollContentBy