txtKomm.BackColor = LightenColor(Color.Blue, 0.5)
 
    Private Function LightenColor(color As Color, correctionFactor As Single) _
      As Color
 
        Dim red As Single = (255 - color.R) * correctionFactor + color.R
        Dim green As Single = (255 - color.G) * correctionFactor + color.G
        Dim blue As Single = (255 - color.B) * correctionFactor + color.B
 
        Return color.FromArgb(color.A, CInt(red), CInt(green), CInt(blue))
 
    End Function