Not new to Mac, but having a display issue.

I'm running 10.5.8 on a Macbook. I was using my iPad as a second display via the iDisplay app. After my curiosity was sated, I closed the app on the iPad and on the desktop, and now I can't get my display settings back to normal. I've tried all the available dimensions the Display preferences offer. When I open display preferences it gives me the options for my main display as well as the VGA display, even though no other display is currently connected? Does this makes sense? I've been using Mac for years but have never encountered a display issue...

 

Thank you.