Arrow up and Arrow down are not working as well as slimscroll doesn't scroll on clicking on rails

The main functions of a scrollbar is it works on mousewheel scroll, one can double click an drag the scrollbar and these functionalities works properly in slimscroll but the arrow up and arrow down keys are not working at all ... as well as click on a path(rail) slimscroll doesn't scroll. Please add this two functionalities in slimscroll.
