parent pages, and drop-down menu from tab?

i have set up a page using the master suite theme. i am having troubles with the tabs- i have a tab called “our services”, and that page is the parent page for several others (specific services). in other themes i have used, making pages under a parent page results in a drop-down menu showing up when you hover over the tab of the parent page, allowing you to see the pages under that “parent”, but this is not happening in this theme… so any pages i create that have a “parent” are not showing up at all.

any advice?