public TabbedDocumentManager()
{
//InitializeComponent();
//btnClose.Image = Resources.ResourceManager.GetBitmap("CloseButton.ico");
//btnListAll.Image = Resources.ResourceManager.GetBitmap("ListAllButton.ico");
_panes = new List<ContentDocument>();
_panesInOrderUsed = new List<ContentDocument>();
//ShowControlAsEmpty();
//toolTipManager.SetToolTip(btnClose, "Close");
//toolTipManager.SetToolTip(btnListAll, "List active windows");
}