[STAThread]
static void Main()
{
    Application.EnableVisualStyles();
    Button button;
    TextBox textbox;

    using (Form form = new Form
    {
        Controls ={
            new TabControl { Dock = DockStyle.Fill, TabPages = {
                new TabPage { Text = "Tab Page", Controls = {
                    (textbox = new TextBox { Text = "I'm a graph control...",
                        Multiline = true, Dock = DockStyle.Fill})
                }}
            }},
            (button = new Button { Text = "Maximize", Dock = DockStyle.Bottom }),
    }}) {
        button.Click += delegate
        {
            textbox.Parent.Controls.Remove(textbox);
            form.Controls.Add(textbox);
            textbox.BringToFront();
        };
        Application.Run(form);
    }
}