Thank you for your post.
The change in FileMaker Pro 14 caused other issues, so it was removed in FileMaker Pro 15. Refresh Object is about refreshing the named object and not objects in front/behind it. If you remove the rectangle object name "leftNav", and then group the three buttons along with the rectangle object and give it the name "leftNav", then it will work. You may also want to consider replacing the rectangle with a Slide control as Refresh Object will update all descendant objects.
OK, thanks for the confirmation (& suggestions)