VS 2013 [RESOLVED] Sub refuses to cooperate.

Private Sub ctmFormat_Click(sender As Object, e As EventArgs) Handles ctmFormat.Click
        Dim rb As RichTextBox = GetRTBFocus(sender)
        If rb Is Nothing Then Exit Sub
        Conv(rb)
        Highlight(rb)
End Sub

Private Function GetRTBFocus(sender As Object) As RichTextBox
        Dim c As Control = DirectCast(DirectCast(sender, ToolStripMenuItem).Owner, ContextMenuStrip).SourceControl
        Dim rb = DirectCast(c, RichTextBox)
        Return (RB)
End Function

Public Sub Conv(ByVal rtb As RichTextBox)
        'convert Text to Sentence Case
        rtb.Text = rtb.Text.ToLower
 
        Dim sentences() As String = rtb.Text.Split(New String() {". ", "? ", "! ", Chr(10) & Chr(10), "." & Chr(10)}, StringSplitOptions.RemoveEmptyEntries)
        Dim newSentences() As String = DirectCast(sentences.Clone, String())
 
        Dim searchStart As Integer = 0
        For x As Integer = 0 To sentences.GetUpperBound(0)
 
            sentences(x) = sentences(x).Trim
            newSentences(x) = newSentences(x).Trim
            newSentences(x) = newSentences(x).Substring(0, 1).ToUpper & newSentences(x).Substring(1).Replace(" i ", " I ").Replace(" i'", " I'")
 
            Dim start As Integer = rtb.Text.IndexOf(sentences(x), searchStart)
            For c As Integer = start To start + sentences(x).Length - 1
                rtb.SelectionStart = c
                rtb.SelectionLength = 1
                rtb.SelectedText = newSentences(x).Substring(c - start, 1)
            Next
            searchStart += sentences(x).Length + 2
        Next
End Sub

Public Sub Highlight(ByVal r As RichTextBox)
    r.SelectAll()
    r.SelectionColor = Color.White
    r.DeselectAll()
 
    For Each strWord As String In ObjectList
        Dim startIndex As Integer = 0
        Dim wordMatchers As New Regex(String.Format("\b{0}(\b\S|\b)", strWord))
        For Each wMatch As Match In wordMatchers.Matches(r.Text)
            With r
                .Find(wMatch.Value, startIndex, RichTextBoxFinds.WholeWord)
                .SelectionColor = Color.Lime
                .SelectedText = StrConv(.SelectedText, VbStrConv.ProperCase)
                startIndex = .SelectionStart
            End With
        Next
    Next
End Sub