private void deleteItem_Click(object sender, EventArgs e)
        {
            GridViewColumnGroup group        = this.GridViewGroupColumn.Group;
            GridViewTemplate    viewTemplate = this.ViewTemplate;

            if (group == null)
            {
                return;
            }
            this.HideColumnsInGroup(group);
            if (group.Parent != null)
            {
                group.Parent.Groups.Remove(group);
            }
            else if (group.ParentViewDefinition != null)
            {
                group.ParentViewDefinition.ColumnGroups.Remove(group);
            }
            this.TableElement.ViewElement.RowLayout.InvalidateLayout();
            this.TableElement.ViewElement.RowLayout.InvalidateRenderColumns();
            this.TableElement.ViewElement.UpdateRows(true);
            this.TableElement.UpdateView();
            viewTemplate?.OnNotifyPropertyChanged("ViewDefinition");
        }