protected override void OnShutdown()
        {
            //trash every form and its resources still open on shutdown.
            if (zoekAdresDlg != null)
            {
                if (!zoekAdresDlg.IsDisposed)
                {
                    zoekAdresDlg.Dispose();
                }
            }

            if (reverseDlg != null)
            {
                if (!reverseDlg.IsDisposed)
                {
                    reverseDlg.Dispose();
                }
            }

            if (poiDlg != null)
            {
                if (!poiDlg.IsDisposed)
                {
                    poiDlg.Dispose();
                }
            }

            if (gipodDlg != null)
            {
                if (!gipodDlg.IsDisposed)
                {
                    gipodDlg.Dispose();
                }
            }

            if (capakayDlg != null)
            {
                if (!capakayDlg.IsDisposed)
                {
                    capakayDlg.Dispose();
                }
            }

            if (batchGeocodeDlg != null)
            {
                if (!batchGeocodeDlg.IsDisposed)
                {
                    batchGeocodeDlg.Dispose();
                }
            }

            if (elevationDlg != null)
            {
                if (!elevationDlg.IsDisposed)
                {
                    elevationDlg.Dispose();
                }
            }

            if (catalogDLg != null)
            {
                if (!catalogDLg.IsDisposed)
                {
                    batchGeocodeDlg.Dispose();
                }
            }

            if (settingsDlg != null)
            {
                if (!settingsDlg.IsDisposed)
                {
                    settingsDlg.Dispose();
                }
            }

            if (aboutDlg != null)
            {
                if (!aboutDlg.IsDisposed)
                {
                    aboutDlg.Dispose();
                }
            }

            saveSettings();

            base.OnShutdown();
        }