Your code looks good, you just need to set DrawFill
to true
Add this:
e.RowElement.DrawFill = true;
Full example:
void grid_RowFormatting(object sender, Telerik.WinControls.UI.RowFormattingEventArgs e)
{
if (e.RowElement.RowInfo.Cells["CODE"].Value.ToString() == "X"))
{
e.RowElement.DrawFill = true;
e.RowElement.BackColor = System.Drawing.Color.Aqua;
}
}