In you save button put :
private void btnSave_Click(object sender, EventArgs e)
{
x = 4;
y = panel1 .Controls.Count * 70;
Button newButton = new Button ();
newButton.Height = 150;
newButton.Width = 60;
newButton.Location = new Point(x, y);
newButton.Text= "your text";
newButton.Click += new
System.EventHandler(Button_Click);
tabControl1.TabPages [0].Controls.Add(newButton);
}
And also you can handel the click of new button created :
public void Button_Click(object sender, EventArgs e)
{
Button button = (Button)sender ;
MessageBox.Show("Button is pressed "+button .Text );
}