public void mouseDragged(MouseEvent e) {

        if (documentViewController != null ){
            int userToolModeFlag = documentViewController
                            .getDocumentViewModel().getViewToolMode();
            if (userToolModeFlag == DocumentViewModel.DISPLAY_TOOL_ZOOM_IN ||
                    userToolModeFlag == DocumentViewModel.DISPLAY_TOOL_ZOOM_OUT) {
                // record that we are doing a drag box zoom.
                isDragZoom = true;
            }
        }
    }