To reproduce: -add a RadGridView and a RadButton; use the following code: public Form1() { InitializeComponent(); //Create a child template GridViewTemplate childTemplate = new GridViewTemplate(); childTemplate.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill; this.radGridView1.Templates.Add(childTemplate); GridViewRelation relation = new GridViewRelation(); relation.ChildTemplate = childTemplate; relation.ParentTemplate = this.radGridView1.MasterTemplate; relation.ChildColumnNames.Add("B1"); relation.ParentColumnNames.Add("A1"); this.radGridView1.Relations.Add(relation); } private DataTable dtParent; private DataTable dtChild; private void Form1_Load(object sender, EventArgs e) { //Add data dtParent = new DataTable(); dtParent.Columns.AddRange(new DataColumn[] { new DataColumn("A1") }); dtChild = new DataTable(); dtChild.Columns.AddRange(new DataColumn[] { new DataColumn("B1"), new DataColumn("B2") }); DataRow dr = dtParent.NewRow(); dr["A1"] = "0"; dtParent.Rows.Add(dr); for (int i = 0; i < 40; i++) { DataRow drChild = dtChild.NewRow(); drChild["B1"] = "0"; drChild["B2"] = ""; dtChild.Rows.Add(drChild); } this.radGridView1.MasterTemplate.DataSource = dtParent; this.radGridView1.Templates[0].DataSource = dtChild; } private void radButton1_Click(object sender, EventArgs e) { DataRow drNew = this.dtChild.NewRow(); drNew["B1"] = "0"; drNew["B2"] = "New"; this.dtChild.Rows.Add(drNew); } 

If you expand the first parent row and scroll down to the last child row, clicking over the button does not refresh the vertical scroll-bar correctly. The new row shows only half. You can not scroll to the end. 

Workaround: refresh the vertical scroll-bar manually: private void radButton1_Click(object sender, EventArgs e) { DataRow drNew = this.dtChild.NewRow(); drNew["B1"] = "0"; drNew["B2"] = "New"; this.dtChild.Rows.Add(drNew); int val = radGridView1.TableElement.VScrollBar.Value; foreach (GridViewRowInfo row in radGridView1.Rows) { if (row.IsExpanded) { val = radGridView1.TableElement.VScrollBar.Value; row.IsExpanded = false; row.IsExpanded = true; radGridView1.TableElement.VScrollBar.Value = val; } } }