// Make this panel the current one. Remove from previous
        // position in list and re-add in front of current panel
        public void MakePanelCurrent()
        {
            if (SuperPuTTY.MainForm.CurrentPanel == this)
                return;

            // Remove ourselves from our position in chain
            this.PreviousPanel.NextPanel = this.NextPanel;
            this.NextPanel.PreviousPanel = this.PreviousPanel;

            this.PreviousPanel = SuperPuTTY.MainForm.CurrentPanel;
            this.NextPanel = SuperPuTTY.MainForm.CurrentPanel.NextPanel;
            SuperPuTTY.MainForm.CurrentPanel.NextPanel = this;
            this.NextPanel.PreviousPanel = this;

            SuperPuTTY.MainForm.CurrentPanel = this;
        }
        protected override void OnFormClosed(FormClosedEventArgs e)
        {
            base.OnFormClosed(e);

            if (SuperPuTTY.MainForm == null) return;

            // only 1 panel
            if (SuperPuTTY.MainForm.CurrentPanel == this && this.NextPanel == this && this.PreviousPanel == this)
            {
                SuperPuTTY.MainForm.CurrentPanel = null;
                return;
            }

            // Remove ourselves from our position in chain and set last active tab as current
            if (this.PreviousPanel != null)
            {
                this.PreviousPanel.NextPanel = this.NextPanel;
            }
            if (this.NextPanel != null)
            {
                this.NextPanel.PreviousPanel = this.PreviousPanel;
            }
            SuperPuTTY.MainForm.CurrentPanel = this.PreviousPanel;

            // manipulate tabs
            if (this.DockHandler.Pane != null)
            {
                int idx = this.DockHandler.Pane.Contents.IndexOf(this);
                if (idx > 0)
                {
                    IDockContent contentToActivate = this.DockHandler.Pane.Contents[idx - 1];
                    contentToActivate.DockHandler.Activate();
                }
            }
        }