I think... bug with "TextPrinter".

class A : Form
{
// When I use "TextPrinter" object like class member
TextPrinter tp = new TextPrinter(TextQuality.High);
Font text_font = new Font("Verdana", 10);

void Render()
{
// first string: "Hello"
GL.LoadIdentity();
GL.Translate(0, 100, 0);
tp.Print("Hello", text_font, Color.White);

// second string: "Hello"
GL.LoadIdentity();
GL.Translate(0, 200, 0);
// here Color.Red is ignored and used previous Color.White, because strings are same
tp.Print("Hello", text_font, Color.Red);

// other string: "Hello again"
GL.LoadIdentity();
GL.Translate(0, 300, 0);
// changing of color works again, but string must be different
tp.Print("Hello again", text_font, Color.Red);
}
}

Is it bug or my mistake?