[RESOLVED] find and color text red in a richtextbox each time the find button is clicked

[isnoend07]

Private Sub cmdFind_Click()
Dim str As String
Dim Start As Integer
Dim Length As Integer
str = txtFind
Length = Len(str)
Start = rtfBills.Find(str, , , rtfWholeWord)
With rtfBills
.SelStart = Start
.SelLength = Length
.SelColor = vbRed
End With

This works fine for finding the first occurrence of a word, but need it modified to find the next occurrence of the word with each button click
How to do this ?