Currently when clicking on the expander cell RadGridView scrolls to the currently selected column which in some cases causes unnecessary scrolling

Workaround:
public class CustomGridControl : RadGridView
{
    public override string ThemeClassName
    {
        get
        {
            return typeof(RadGridView).FullName;
        }
        set
        {
        }
    }
 
    protected override void OnMouseDown(MouseEventArgs e)
    {
        RadElement element = this.ElementTree.GetElementAtPoint(e.Location);
        GridGroupExpanderCellElement expanderCell = element as GridGroupExpanderCellElement;
        if (expanderCell == null)
        {
            expanderCell = element.FindAncestor<GridGroupExpanderCellElement>();
        }
        if (expanderCell != null)
        {
            this.TableElement.BeginUpdate();
            expanderCell.RowInfo.IsExpanded = !expanderCell.RowInfo.IsExpanded;
            this.TableElement.HScrollBar.Value = 0;
            this.TableElement.EndUpdate();
            return;
        }
 
        base.OnMouseDown(e);
    }
}