public void SelectLabel(Label l)
        {
            (l.Tag as LabelTag).Selected = true;
            SelectedLabels.Add(l);
            l.BorderStyle = BorderStyle.FixedSingle;

            // Fire event "SelectedLabelsChanged"
            SelectedLabelsChanged(null, null);
        }
        public void SelectAllLabels()
        {
            SelectedLabels.Clear();

            // Performance boost
            Container.SuspendLayout();
            if (Container.Controls.Count > 200)
                Container.Visible = false;

            foreach (Control c in Container.Controls) {
                (c.Tag as LabelTag).Selected = true;
                SelectedLabels.Add(c);
                (c as Label).BorderStyle = BorderStyle.FixedSingle;
            }

            Container.SuspendLayout();
            Container.Visible = true;

            // Fire event "SelectedLabelsChanged"
            SelectedLabelsChanged(null, null);
        }