
I'm still having this problem (obviously) and I'm still using the workaround below, but it annoys me and seems like I'm just missing something simple. Any takers now—10 months later?

Using Vault 2.0.1, if I extract a new file (that's not in my project) to disk, and then go into my project and Show/Hide all files (refresh from disk), I can see that the new file isn't in my project (grey'd out). Since my project file itself is not read-only, I should just be able to right-click on the file in question and "Include in Project." That does work and VS makes the appropriate modifications to the project file. The problem is that somewhere along the way the file I'm "including" gets checked out (and I didn't ask for that to happen).
Is there a setting for this because it doesn't seem like that should happen. I can work around it by undoing the check-out and reverting the file back, but it's hokey! =)