Hello @ExSub! Welcome to Ext.NET forums!
I can't really run your code, and I don't see any relevant line of the logic you describe in what you shared, so I can get little clue from it, so that would be as far as I could get in trying to help you with the information I have:
One way you may be able to store the selection of a grid is using the Stateful property
; this can basically be used to remember column settings like position, hidden state, widths...
If that's not what you're looking for, then maybe this one helps: Remote Paging Checkbox selection
. While still for version 1, I believe the way you'd save a selection for later restoring it will be very close to the approach there, if not the exact same.
I hope this helps!