Question:
I've build my application stacks - I'm assuming I need to confirm them with a checkbox I see but I don't know what happens once I confirm a stack?
Answer:
Confirming an app stack will lock those devices in the group and cause the devices in that group to be ineligible for future grouping (rerunning build app stacks). If you create a custom group, and do NOT confirm that stack, rerunning build app stacks will delete the custom stack and all devices in that stack will be regrouped based on the traffic and the type of auto-grouping that is selected.