private void SetActivePane()
            {
                DockPane value = GetPaneFromHandle(NativeMethods.GetFocus());
                if (m_activePane == value)
                    return;

                if (m_activePane != null)
                    m_activePane.SetIsActivated(false);

                m_activePane = value;

                if (m_activePane != null)
                    m_activePane.SetIsActivated(true);
            }