private void RichText(object sender, EventArgs e) { var rtf = new Rtf.Builder(); rtf.TextStyle = new Rtf.TextStyle { FontIndex = rtf.FontIndex(Rtf.FontDesc.CourierNew), FontStyle = Rtf.EFontStyle.Bold | Rtf.EFontStyle.Underline, ForeColourIndex = rtf.ColourIndex(Color.Red), BackColourIndex = rtf.ColourIndex(Color.Green), FontSize = 18, }; rtf.Append("Heading\n"); rtf.TextStyle = Rtf.TextStyle.Default; rtf.Append("More Rtf text"); var content = rtf.ToString(); Rylogic.Gui.WinForms.HelpUI.ShowDialog(this, Rylogic.Gui.WinForms.HelpUI.EContent.Rtf, "RTF Help", content); }