ios - UIToolbar gets pushed off screen when moving between controllers -

ok doesn't seem coding issue more has storyboard/layout. i've searched around stackoverflow , elsewhere possible solution of responses i've seen, might bug ios6. though i'm wondering if else has come across issue:

basically, have view controller nav bar on top , tool bar on bottom. taking entire screen uiimage. issue when go view controller, of time toolbar on bottom, , of time looks it's getting pushed off uiimage. if shrink uiimage isn't touching toolbar resolves issue, leave white gap between toolbar , uiimage. has else ever experienced this?

edit: i've found workaround. basically, selected both uiimage , uitoolbar , pinned respective heights keep them constant no matter what. though, admit doesn't explain issue having.

the problem caused constraint settings each element. under size inspector can adjust settings. want navbar static @ top of screen, toolbar static @ bottom of screen, , imageview stretch between them.

another cause if using -initwithimage because adjust size of frame match size of specified image. if image several pixels tall push toolbar off screen. solution in case use -initwithframe on uiimageview , set image property.