/// <summary>
/// For any mdi child form that closes updates the variable with the sum,
/// and updates the status bar
/// </summary>
/// <param name="sender">Standard sender object</param>
/// <param name="e">Standard event object</param>
private void MdiChildClosed(object sender, FormClosedEventArgs e)
{
MdiChilrenSum--;
tslblMdiChildNumber.Text = MdiChilrenSum.ToString();
}
/// <summary>
/// When any form is opened updates the status bar with the number of mdi children
/// </summary>
/// <param name="sender">Standard sender object</param>
/// <param name="e">Standard event object</param>
private void MenuMDIUI_MdiChildActivate(object sender, EventArgs e)
{
tslblMdiChildNumber.Text = MdiChilrenSum.ToString();
}