1. How to add new widgets in sidebar?
If you want to add some new widgets to your sidebar, you have to edit HTML.
Change this line.sidebar {display:none;} to .sidebar {display:block;} after that you will see widget box in your widget section. Just add some new widget now, save and after that change .sidebar to .sidebar {display:none;} again.
2. Why shadow doesn't work in IE?
IE doesn't support text-shadow. I don't know why, ask Bill Gates.