1. Define a custom AggregateFunction for a column 2. Group on a column 3. A calculation on the AggregateFunction is invoked 3. The Grouping.Key (of the input parameter) corresponds to the correct key 4. Edit a value on the column (having the AggregateFunction) 5. A calculation is invoked, but the Grouping.Key is "1" and not the correct key.
To avoid recreating the groups after property/collection change, RadGridView mimics grouping while recalculating the aggregate values. This is achieved by defining QueryableAggregatesGroupDescriptors for the separate aggregate functions. They are applied to every sequence of items that belong to a single group, serving the only purpose to apply the aggregate expression to the items in the group. Aiming to ensure that this "fake grouping" will not create unneeded subgroups, these descriptors' implementation uses constant key value (1), so that the observed behavior is the expected one. Please open a support ticket if it impedes you from achieving a specific goal.