                             forControlEvents: .TouchUpInside)
     forwardButton.translatesAutoresizingMaskIntoConstraints = false
     addSubview(forwardButton)
+
+
+    backButton.enabled = currentMonth.numberOfMonthsUntil(firstMonth) != 0
+    forwardButton.enabled = currentMonth.numberOfMonthsUntil(lastMonth) != 0
+    setupButtonConstraints()
+  }
+
+  private func setupButtonConstraints() {
+    removeConstraints(backButton)
+    removeConstraints(forwardButton)
+    addConstraints(NSLayoutConstraint
+      .constraintsWithVisualFormat("H:|-0-[backButton(44)]",
+        options: [.AlignAllLeading], metrics: nil,
+        views: ["backButton": backButton]))
+    addConstraints(NSLayoutConstraint
+      .constraintsWithVisualFormat("V:|-0-[backButton(\(headerHeight))]",
+        options: [.AlignAllLeading], metrics: nil,
+        views: ["backButton": backButton]))
+
     addConstraints(NSLayoutConstraint
       .constraintsWithVisualFormat("H:[forwardButton(44)]-0-|",
         options: [.AlignAllLeading], metrics: nil,
         views: ["forwardButton": forwardButton]))
     addConstraints(NSLayoutConstraint
-      .constraintsWithVisualFormat("V:|-0-[forwardButton(44)]",
+      .constraintsWithVisualFormat("V:|-0-[forwardButton(\(headerHeight))]",
         options: [.AlignAllLeading], metrics: nil,
         views: ["forwardButton": forwardButton]))
 
-    backButton.enabled = currentMonth.numberOfMonthsUntil(firstMonth) != 0
-    forwardButton.enabled = currentMonth.numberOfMonthsUntil(lastMonth) != 0
   }
 
   private func setupMonthLabel() {

                         forControlEvents: .TouchUpInside)
    backButton.translatesAutoresizingMaskIntoConstraints = false
    addSubview(backButton)
    addConstraints(NSLayoutConstraint
      .constraintsWithVisualFormat("H:|-0-[backButton(44)]",
        options: [.AlignAllLeading], metrics: nil,
        views: ["backButton": backButton]))
    addConstraints(NSLayoutConstraint
      .constraintsWithVisualFormat("V:|-0-[backButton(44)]",
        options: [.AlignAllLeading], metrics: nil,
        views: ["backButton": backButton]))

    forwardButton.setImage(MayaButtonImage.rightArrowImage, forState: .Normal)
    forwardButton.tintColor = UIColor.blackColor()

    let currentPage = self.collectionView.contentOffset.x / self.collectionView.frame.size.width
    return Int(round(currentPage))
  }

  private func removeConstraints(view: UIView) {
    var list = [NSLayoutConstraint]()
    if let superview = view.superview {
    for constraint in superview.constraints {
      if constraint.firstItem as? UIView == view || constraint.secondItem as? UIView == view {
        list.append(constraint)
      }
    }
    view.superview?.removeConstraints(list)
    view.removeConstraints(view.constraints)
  }

}