Use attached to reproduce. Workaround: RadTextBox tb = new RadTextBox(); tb.Font = new Font(Font.Name, 12F, FontStyle.Bold); tb.MaxLength = 200; tb.Name = "textBox1"; tb.Text = "<Required>"; tb.Location = new Point(49, 7); var pixels = tb.Font.SizeInPoints * 96 / 72; tb.TextBoxElement.TextBoxItem.HostedControl.MinimumSize = new Size(0, (int)pixels + 6);