Right now I am using some buttons with the following code:
richTextBox1.SelectionFont = new Font(\"Tahoma\", 12, FontStyle.Bold);
richTextBox1.SelectionColor = S
you need to do something like this..
in order ot make it italic.
richTextBox1.SelectionFont = new Font("Tahoma", 12, richTextBox1.SelectionFont.Style | FontStyle.Italic);
//in order to make it bold
richTextBox1.SelectionFont = new Font("Tahoma", 12, richTextBox1.SelectionFont.Style | FontStyle.Bold);