private void button5_Click(object sender, EventArgs e)
{
ChronologicalGraph f4 = new ChronologicalGraph();
this.Hide();
f4.ShowDialog();
}
private void linkLabel6_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
{
ChronologicalGraph c = new ChronologicalGraph();
this.Hide();
c.ShowDialog();
}