NanoScroller not triggering itself

The code below should be able to trigger the pane and slider to appropriate display css properties according to nanoscroller documentation. However, the scroller doesn't show the slider until I do some action in browser such as pressing F12 to fireup firebug or right clicking an element inside to inspect it. What could possibly be going wrong?

        $(".nano").nanoScroller({
        alwaysVisible: true,
        scroll: "bottom"    
    });