private void openURLInSomeViewer(URL url) {
        // openDocument the URL
        if (document == null) {
            openDocument(url);
        } else if (windowManagementCallback != null) {
            int oldTool = SwingController.this.getDocumentViewToolMode();
            setDisplayTool(DocumentViewModelImpl.DISPLAY_TOOL_WAIT);
            try {
                windowManagementCallback.newWindow(url);
            } finally {
                setDisplayTool(oldTool);
            }
        }
    }