I wonder why the demo page works correctly? It also freezes the active group on top of the grid when scrolling down.  This is the functionality that I need.

Thank you. 

Thanks for the sample.  I ran your example and If I choose the Split header display mode and expand Canada, you will see the Group disappears and I can't get to it anymore.  After this all the Group are not functioning correctly anymore…expand USA, then collapse it…expand other Countries.

Also, setting the IsGroupExpandedDefault="true"  produces the same issue as above.  However, removing this attribute altogether renders the groupings and expansion/collapse correctly, with the downside of having all groups expanded.

Interestingly, the demo page does not suffer the same problem:

https://infragistics.com/blazorsite/components/data-grid-row-grouping.html

The IsGroupExpandedDefault = false collapsed the groupings by default as expected.  But, I think there is a bug in the grid, I have 4 group levels and now expanding the groups causes the grid to hide the upper groups.

I already have that attribute set but when it renders at runtime all the groupings are expanded.  How can I have all the groupings collapsed by default?