internal void Expand(GroupedItemViewModel grp)
{
int pos = entries.IndexOf(grp);
entries.RemoveAt(pos);
entries.InsertRange(pos, grp.Items);
FirePropertyChanged("Items");
}
internal void Collapse(GroupedItemViewModel grp)
{
ItemViewModel first = grp.First;
int firstPos = entries.IndexOf(first);
entries.RemoveRange(firstPos, grp.Count);
entries.Insert(firstPos, grp);
FirePropertyChanged("Items");
}
