In your IsChildVisible override, check for a GridSummarySection and return true to always see it.
public override bool IsChildVisible(Element el)
{
if (el is GridSummarySection)
{
return true;
}
else if (el is CaptionSection)
{
if (this.Details == null || this.Records.Count == 0 || this.Records.Count > 1)
return true;
else
return false;
}
else if (el is DetailsSection)
{
if (this.Details == null || this.Records.Count == 0 || this.Records.Count > 1)
return el.ParentGroup.IsExpanded;
else
return true;
}
else
return el.ParentGroup.IsExpanded;
}