Closed Unassigned: Package restore should try to restore from other enabled package sources when it failed with Active Package Source [3437]

1. create a c# class library.
2. Right Click Solution and choose 'Enable Package Restore'. Click yes on the dialog.
3. Install a package to the project.
4. Add a customer source feed at NuGet option Settings Dialog.
5. Start Package console Manager and select the custom source feed.
6. Close the console and close VS.
7. Using explorer, navigate to the solution folder and delete the "packages" folder.
8. Open the project, and launch Manage NuGet Package dialog.
9. Verify a yellow bar display and a 'Restore' button on the bar.
10.Click the Restore button.
Expect: The package restored succesful and the yellow disappear.
Actual: restore failed and the yellow won't disappear.

Comments: verified it now looks at other enabled package sources