private void button15_Click(object sender, EventArgs e)
{
Disseny disseny = new Disseny();
disseny.ShowDialog();
Close();
}
private void toolStripMenuItem2_Click(object sender, EventArgs e)
{
Disseny newMDIChild = new Disseny();
// Set the Parent Form of the Child window.
newMDIChild.MdiParent = this;
// Display the new form.
newMDIChild.Show();
toolStripMenuItem2.Enabled = false;
toolStripMenuItem1.Enabled = true;
}