Hi Stefano,
We have analyzed your reported issue, In Virtual scroll mode the scroller height depends on the number of rows created initially under the grid. We cant select row which are not loaded during Virtual Scrolling “On-demand Paging” concept.
Note : if you want to load more records initially, please increase the scroller height.
If we misunderstood your requirement please get back with more information.
Please let us know if you have any queries.
Regards,
J.Mohammed Farook