Incorrect version of multiple top-level bindings of the same name from the same interactive submission is displayed

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Submit the following in FSI: `let x = 3;; let x = 4;; let x = 5;; let x = 
6;;`

What is the expected output? 
The watch window should show x = 6 (the most recent binding to x)

What do you see instead?
The watch window shows x = 3 (the first binding to x)

Original issue reported on code.google.com by stephen....@gmail.com on 5 Jul 2013 at 11:40