Scroller not displaying in Lighting option tab under 3D and Materials

Hi there,

When I was using the 3D and Materials panel and went to the Lighting tab, I couldn't go further down to work on the Shadow options because there was no scroller there that would allow me to do so (it was supposed to be on the right side of the tab?). Please see the attached screenshot. Any tips and suggestions will be much appreciated. Many thanks.