private void ShowAccountForm()
 {
     if (accountForm != null)
     {
         accountForm.Activate();
         accountForm.Update();
         if (accountForm.WindowState == FormWindowState.Minimized)
         {
             accountForm.WindowState = FormWindowState.Normal;
         }
     }
     else
     {
         accountForm = new AccountForm(controller);
         accountForm.Show();
         accountForm.Activate();
         accountForm.BringToFront();
         accountForm.FormClosed += accountForm_FormClosed;
     }
 }
 void accountForm_FormClosed(object sender, FormClosedEventArgs e)
 {
     accountForm = null;
     Util.Utils.ReleaseMemory();
 }