The word is not in the form of smooth throughout, with the following code:
private void Form1_Load(object sender, EventArgs e)
{
label1.ForeColor = Color.Violet;
label1.Text = "From trong suốt";
label2.ForeColor = Color.BlueViolet;
label1.Text = "Mu chữ của form";
label3.ForeColor = Color.DarkOrange;
label1.Text = "Mu chữ của form";
this.TransparencyKey = Color.Wheat;
this.BackColor = Color.Wheat;
}

why not borrow the word transparent form? way to overcome this is not the case? image link: http://freakshare.com/files/1lh6461j/formtran.jpg.html