public AccordionButton Add(string itemText, Control container)
{
int visibleItems = 0;
for (int i = 0; i < Controls.Count; i++)
if (Controls[i].Visible)
visibleItems++;
AccordionButton itemButton = new AccordionButton(this);
itemButton.Anchor = AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Top;
itemButton.Location = new Point(0, visibleItems * (ItemHeight + ItemSpace));
itemButton.Width = Width;
itemButton.Text = itemText;
container.Visible = false;
Controls.Add(itemButton);
Controls.Add(container);
Refresh();
return itemButton;
}