I have a popover containing a UINavigationController. I can display the popover fine, and it contains the navController just fine. The navController contains a tableView a
This stuff may have worked once but not with xCode 6 wherein contentSizeForViewInPopover is deprecated. Luckily it's respected at storyboard load time. I downloaded an xml editor (Xmplify) and hacked the storyboard. Set the key contentSizeForViewInPopover to the size you want. Save and replace (make a copy first) storyboard.
More specifically :
< viewController>
<value key="contentSizeForViewInPopover" type="size" width="450" height="280" / >
</viewController>