VSCode Version: 1.12.1
OS Version: OS X EI Capitan 10.11.3

Steps to Reproduce:

1. Open some project from GitHub.
2. Open a file A.cs which has no fresh changes at all.
3. Stay on the editor of A.cs, and notice the button of Open Changes on the top right corner above the editor doesn't display as disbled! Clicking it has no effect of course, but it should display as disable in this case just like what in the old versions.