rich text boxes

[adzzzz]

Private Sub cmdAddText_Click()
rtfTesting.Text = txtToAdd & vbCrLf & rtfTesting.Text
rtfTesting.SelStart = 0
rtfTesting.SelLength = Len(txtToAdd)
rtfTesting.SelColor = vbRed
End Sub

when i click the command button, the top line of my textbox changes which it what i want but then ALL of the lines underneath it are reverted to the last colour of the top line? i've looked at the .TextRTF in a normal textbox and can see why this happens but i havent got a clue how to get round it anyone?
- cheers