I saw in console that whenever I open my datepicker that I get 404 Not found error for this image file ui-bg_glass_75_e6e6e6_1x400.png
I downloaded the image from github and put it in my local under jquery-ui
folder. Now the problem is solved.
Other image files found here:
https://github.com/julienw/jquery-trap-input/tree/master/lib/jquery/themes/base/images