TextRendering in panel only works when it's behind a label

Question

I'm using TextRenderingHint.AntiAliasGridFit to render my text, because my text looks very bad when I don't.

But for some strange reason the text only renders fine when its behind a label (transparant back color).

So I paint the text in a panel and there's a label with the same width as the panel inside it. When the text I paint is behind the label it looks good, else it looks the same as before. Any idea's why?

Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles pnlPanel.Paint

    Dim big_font As New Font("Times New Roman", 60, FontStyle.Bold, GraphicsUnit.Pixel)    
    e.Graphics.TextRenderingHint = TextRenderingHint.AntiAliasGridFit
    e.Graphics.DrawString("Text", big_font, Brushes.Black, 10, 80)

End Sub

Please tell me if there are better ways to get a smoother text.

Thanks