Toad 126.96.36.199. Team coding with TFS. I do a check out in the TC Manager on a file where the code is different than what is in TFS. The Different Versions popup appears. If I click Cancel, the popup closes and it looks like it cancelled from the viewpoint of Toad: the file shows as available from both the VCS and Team Projects tabs, but the file is actually checked out in TFS, as I see from the Team Explorer in Visual Studio. The same behavior occurs if I select View Differences.
The test above was done on a view. I also ran a similar test on a package where the spec and body are checked out in tandem. Here is what I found. I checked out the spec, got the Different Versions popup, clicked Cancel. Like above, the spec looks like it is not checked out in the TC Manager, but the body does show as being checked out. Visual Studio shows both are checked out. In the TC Manager, I undo the checkout of the body, and now both body and spec are shown as available. Visual Studio shows that the body is no longer checked out, but the spec still is.