This should be part of the docs…
Anyway:
http://developer.coronalabs.com/forum/2012/02/23/popup-choose-file-arrow-problem
Or specifically:
casenum:12439 iPad: Modified media.show API to use table parameters to allow extra parameters to control the popover location and arrow direction to deal with an Apple rejection issue for iPad. media.show( media.PhotoLibrary, { listener = sessionComplete, origin={ xMin=100, yMin=100, xMax=130, yMax=140 }, permittedArrowDirections={“down”,“left”} }). origin is the rect of the button which the popover emerges from.
A convenience programming pattern is to pass the contentBounds of your button: media.show(media.PhotoLibrary, {listener=sessionComplete, origin=myButton.contentBounds}). permittedArrowDirections is an optional field that is an array of allowed directions the popover arrow may point. Valid values are “up”, “down”, “left”, “right”, “any”. “any” is the default. [import]uid: 84637 topic_id: 28347 reply_id: 114500[/import]