You can't have a scroll bar in a text item; you'll need to use a field.
You can then modify the appearance of the field to include a vertical scroll bar.
I've created a text box that displays a data field.
Would appear to indicate that Bob Geltz DOES have a field on his layout. In layout mode, you can select the field and then use the Inspector's data tab to specify that it have a scroll bar. With this specified, the field will no longer pop out when you click/tab into it, but you will now have a scroll bar that you can scroll.