To reproduce: 
1. Add RadGridView with 3 columns and add summary row 
2. When is fired the ViewCellFormatting event, set the Text property of GridSummaryCellElement 
3. Run project and text is not visible. 

void radGridView1_ViewCellFormatting(object sender, CellFormattingEventArgs e) { GridSummaryCellElement summaryCell = e.CellElement as GridSummaryCellElement; if (summaryCell != null) { if (summaryCell.ColumnInfo.FieldName == "ProductID") { summaryCell.Text = "Total"; } } }

Workaround: 
Set FormatString property instead Text 
property void radGridView1_ViewCellFormatting(object sender, CellFormattingEventArgs e) { GridSummaryCellElement summaryCell = e.CellElement as GridSummaryCellElement; if (summaryCell != null) { if (summaryCell.ColumnInfo.FieldName == "ProductID") { summaryCell.FormatString = "Total"; } } }