private void statistikaToolStripMenuItem_Click(object sender, EventArgs e)
 {
     if (frmAdmStatistika == null)
     {
         frmAdmStatistika           = new FrmAdmStatistika();
         frmAdmStatistika.MdiParent = this;
         frmAdmStatistika.Show();
         frmAdmStatistika.Closed += frmAdmStatistika_Closed;
     }
     else
     {
         frmAdmStatistika.Focus();
     }
 }
 private void frmAdmStatistika_Closed(object sender, EventArgs e)
 {
     frmAdmStatistika = null;
 }