TFS unexpected checkout during unbinding/rebinding

Hi guru,

I am using VS2012 and TFS. I found that maybe an issue with following steps.

1. Create a WPF solution (WpfApplication1).
2. Add the solution into TFS and check in.
3. Select File->Source Control->Advanced->Change Source Control.
4. In the popup window, can see two items, Unbind them.
5. Solution unbind from TFS which is good.
6. Then try to re-bind the solution, below dialog pops up.

7. Then I click Check Out, and I can see the solution & project has been check out.

Any one from MSFT can confirm is that an issue from TFS?

Regards,

Yi