/// <summary>
/// This function gets a form, decrement children and show this form
/// if there is no children
/// </summary>
/// <param name="childForm"></param>
private void closeChild(TemplateForm childForm)
{
this.childrenNum--;
if (childrenNum == 0)
this.Show();
}
/// <summary>
/// This function get a form, show it and hide this.
/// It also sets parent field of the form to this.
/// </summary>
private void newChild(TemplateForm childForm)
{
TemplateForm parent = this.parent == null ? this : this.parent;
childForm.parent = parent;
parent.childrenNum++;
parent.Hide();
childForm.Show();
}