Hi John, Studio Pro for Mac (Beta) only contains the Design mode.
Luckily there are two other options in Studio Pro that can help you with viewing and editing the structure of a page. See also the screenshot below.
1. The Page explorer on the left, provides you an editable tree structure of the page.
2. (from Mx 10.9) you can use the X-ray toggle to see the main page elements.
On the top of your page tab there are 2 buttons:
I use the 10.8.1 Beta for Mac.
I don't see this buttons