             self.shareBarButton?.title = NSLocalizedString(editState ? "SharePhotos"  : "SelectPhotos", comment: "")
         }
         
-        updateBarTitle()
-    }
-    
-    func updateBarTitle() {
+        updateShareSelection()
+    }
+    
+    func updateShareSelection() {
         var barTitle = NSLocalizedString(isSharing ? "PickPhotos"  : "DisplayPhotos", comment: "")
         let photoCount = selectedPhotos.count
         if photoCount > 0 {
             barTitle += " (" + String(photoCount) + ")"
         }
+        
+        shareBarButton?.enabled = !isSharing || photoCount > 0
         
         navigationItem.title = barTitle
     }

    override func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
        if isSharing {
            selectedPhotos.append(photos[indexPath.row])
            updateBarTitle()
        }
        else {
            collectionView.deselectItemAtIndexPath(indexPath, animated: true)

        if isSharing {
            let selectedPhoto = photos[indexPath.row]
            selectedPhotos.removeAtIndex(selectedPhotos.indexOf(selectedPhoto)!)
            updateShareSelection()
        }
    }
    
