// mostrar formulario mdi
private void form1ToolStripMenuItem_Click(object sender, EventArgs e)
{
Form9MDI1 fh = new Form9MDI1();
fh.MdiParent = this;
fh.Show();
}
// mostrar formulario mdi
private void form1ToolStripMenuItem_Click(object sender, EventArgs e)
{
Form9MDI1 fh = new Form9MDI1();
fh.MdiParent = this;
fh.Show();
}