private void gridView_CellLoaded(object sender, CellEventArgs e)
{
    if (e.Cell is GridViewFooterCell)
    {
        var row = e.Cell.ParentRow;
        Dispatcher.BeginInvoke(new Action(() =>
        {
            var aggregatesList = row.ChildrenOfType<AggregateResultsList>(); // the exact type of children that should be used to get the new height may vary based on your column Footer contents
            if (aggregatesList.Count() > 0)
            {
                var height = aggregatesList.Max(x => x.ActualHeight);

                var cellsPanel = e.Cell.ParentOfType<GridViewCellsPanel>();
                PropertyInfo minRowHeightProp = cellsPanel.GetType().GetProperty("MinRowHeight", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic);
                object minRowHeightPair = minRowHeightProp.GetValue(cellsPanel);
                PropertyInfo heightProp = minRowHeightPair.GetType().GetProperty("Second");
                heightProp.SetValue(minRowHeightPair, height);
            }
        }));
    }
}