Hi Moorat,
Greetings from the Syncfusion support.
In EJ2Grid Virtualization, data’s are rendered based on the scroller position. At initial rendering, the top records only rendered in DOM. By default, the grouped records will be rendered in expanded state when we performing any action with the virtualization. Since this is the behaviour of Grid.
The collapseAll() methods collapse only the current page tr element in the Grid. So, we cannot achieve your requirement at our end.
Regards,
Balaji Sekar