private void btYourFlashCard_Click(object sender, EventArgs e)
 {
     if (yourFlashCard == null)
     {
         yourFlashCard             = new YourFlashCard();
         yourFlashCard.MdiParent   = this;
         yourFlashCard.FormClosed += new FormClosedEventHandler(YourFlashCard_Close);
         HideElement();
         yourFlashCard.Show();
     }
     else
     {
         yourFlashCard.Activate();
     }
     yourFlashCard.WindowState = FormWindowState.Maximized;
 }
 private void YourFlashCard_Close(object sender, FormClosedEventArgs e)
 {
     ShowElement();
     yourFlashCard = null;
 }