Выделение цветом определенных слов в label

Public Class ColorLabel
  Inherits Control
 
  Private _Money As Decimal = 0
 
  Property Money() As Decimal
    Get
      Return _Money
    End Get
    Set(ByVal value As Decimal)
      _Money = value
      Me.Invalidate()
    End Set
  End Property
 
  Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
    MyBase.OnPaint(e)
 
    Dim moneyText As String = String.Format("{0:N2}", _Money)
    Dim dollarWidth As Integer = TextRenderer.MeasureText(e.Graphics, "$", Me.Font).Width
    Dim moneyWidth As Integer = TextRenderer.MeasureText(e.Graphics, moneyText, Me.Font).Width
 
    TextRenderer.DrawText(e.Graphics, "$", Me.Font, New Point(Me.ClientSize.Width - (dollarWidth + moneyWidth + 2), 2), Color.Red)
    TextRenderer.DrawText(e.Graphics, moneyText, Me.Font, New Point(Me.ClientSize.Width - (moneyWidth + 2), 2), Color.Blue)
  End Sub
 
End Class

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim find As String = "мама"
        If RichTextBox1.Text.Contains(find) Then
            Dim matchString = Regex.Escape(find)
            For Each match As Match In Regex.Matches(RichTextBox1.Text, matchString)
                RichTextBox1.[Select](match.Index, find.Length)
                RichTextBox1.SelectionColor = Color.Green
                RichTextBox1.[Select](RichTextBox1.TextLength, 0)
                RichTextBox1.SelectionColor = RichTextBox1.ForeColor
            Next
        End If
    End Sub

 RichTextBox1.SelectionFont = New Font(RichTextBox1.Font, FontStyle.Bold)
RichTextBox1.SelectionFont = RichTextBox1.SelectionFont