private void операцииПоГПToolStripMenuItem_Click(object sender, EventArgs e)
{
if (f18 == null)
{
f18 = new Form18();
f18.MdiParent = this;
f18.FormClosed += new FormClosedEventHandler(f18_FormClosed);
f18.Show();
}
else
{
f18.Activate();
}
}
void f18_FormClosed(object sender, FormClosedEventArgs e)
{
f18 = null;
}