Access 2007 - tabbed controls on form disappearing

I just created a form with two tab controls. I checked it in form view after I finished the first tab. Looked great. When I checked back after the second, both tabs had disappeared. Now I have my form header and blank space. I can't imagine why. All I did in the in-between time was add controls to the second tab.

Now I can't seem to get the tabs to reappear. This has happened to me before with sub-forms. Any ideas????