Why AppendStyle did not work for me without AddNewLine

I have the following code in PostSave, which tries to save some formated text in a richtext field. Somehow the text style will not be set as specified by richStyle1 or richStyle2 if I don’t have the 1st line with AddNewLine(1). If I have the 1st line, text font and color will be set as expected. But with the new line in the beginning, the rich text field always starts with a blank line which annoys me. Anybody has any idea? Thanks!

Call rtitem.AddNewLine(1)

Call rtitem.AppendStyle(richStyle1)

Call rtitem.AppendText(“Part 1”)

Call rtitem.AppendStyle(richStyle2)

Call rtitem.AppendText(“Part 2”)