xcode - Why the UIButton is so big in a simulator? -

i have uipageviewcontroller , uibutton under it. here screenshot of storyboard.

when build app, button huge:

all of constraints set automatically. tried specify height, doesn't help. ideas?

p.s. i'm using xcode 6.3.

edit:

viewcontroller.swift:

import uikit  class viewcontroller: uiviewcontroller, uipageviewcontrollerdatasource {      @iboutlet weak var restartbutton: uibutton!     var pageviewcontroller: uipageviewcontroller!     var pagetitles: nsarray!     var pageimages: nsarray!      override func viewdidload() {         super.viewdidload()          self.pagetitles = nsarray(objects: "page 1", "page 2")         self.pageimages = nsarray(objects: "algorithm", "apoint")          self.pageviewcontroller = self.storyboard?.instantiateviewcontrollerwithidentifier("pageviewcontroller") as! uipageviewcontroller          self.pageviewcontroller.datasource = self          var startvc = self.viewcontrolleratindex(0) contentviewcontroller         var viewcontrollers = nsarray(object: startvc)          self.pageviewcontroller.setviewcontrollers(viewcontrollers [anyobject], direction: .forward, animated: true, completion: nil)          self.pageviewcontroller.view.frame = cgrectmake(0, 0, self.view.frame.width, self.view.frame.size.height - restartbutton.frame.height)          self.addchildviewcontroller(self.pageviewcontroller)         self.view.addsubview(self.pageviewcontroller.view)         self.pageviewcontroller.didmovetoparentviewcontroller(self)         self.view.sendsubviewtoback(self.pageviewcontroller.view)      }      override func didreceivememorywarning() {         super.didreceivememorywarning()         // dispose of resources can recreated.     }      func viewcontrolleratindex(index: int) -> contentviewcontroller {         if ((self.pagetitles.count == 0) || (index >= self.pagetitles.count)) {             return contentviewcontroller()         }          var vc: contentviewcontroller = self.storyboard?.instantiateviewcontrollerwithidentifier("contentviewcontroller") as! contentviewcontroller         vc.imagefile = self.pageimages[index] as! string         vc.titletext = self.pagetitles[index] as! string         vc.pageindex = index          return vc     }      @ibaction func restartaction(sender: anyobject) {         var startvc = self.viewcontrolleratindex(0) contentviewcontroller         var viewcontrollers = nsarray(object: startvc)         self.pageviewcontroller.setviewcontrollers(viewcontrollers [anyobject], direction: .forward, animated: true, completion: nil)     }      func pageviewcontroller(pageviewcontroller: uipageviewcontroller, viewcontrollerbeforeviewcontroller viewcontroller: uiviewcontroller) -> uiviewcontroller? {          var vc = viewcontroller as! contentviewcontroller         var index = vc.pageindex int          if (index == 0) || (index == nsnotfound) {             return nil         }          index--         return self.viewcontrolleratindex(index)      }      func pageviewcontroller(pageviewcontroller: uipageviewcontroller, viewcontrollerafterviewcontroller viewcontroller: uiviewcontroller) -> uiviewcontroller? {         var vc = viewcontroller as! contentviewcontroller         var index = vc.pageindex int          if index == nsnotfound {             return nil         }          index++          if index == self.pagetitles.count {             return nil         }          return self.viewcontrolleratindex(index)     }      func presentationcountforpageviewcontroller(pageviewcontroller: uipageviewcontroller) -> int {         return self.pagetitles.count     }      func presentationindexforpageviewcontroller(pageviewcontroller: uipageviewcontroller) -> int {         return 0     }  } 

i'm going guess problem have constraint top of button else in interface. rid of constraint. constraints need button @ bottom of screen bottom , right-or-left-or-center - width , height automatic.