Datepicker "Done" button not showing up in Display Button Bar Panel

Datepicker "Done" button not showing up in Display Button Bar Panel

I'm using jQuery UI 1.8.10 and jQuery 1.4.4. I currently have my instance of Datepicker displaying the Button Bar panel that includes the "Today" button, but not the "Done" button. The code I've used to display the button bar is: 

showButtonPanel: true

I thought by default the "Done" button would show when the showButtonPanel is set to "true." Is there something more that I should add? 

I'm using a Mac with OSX and both the latest versions of Firefox and Chrome.

Thanks in advance.