VS2012 Pro and TFS: This is a file that used to be under source control and even the icons next to it I think is showing that it is but when I make a change and right click the option for "Undo Pending Changes" is disabled. However other files in the same project are working fine.
Here is also a screen shot: The file with this issue is Service.asmx.cs
The red check mark next to the file indicates that it is under source control and is checked out. This file is generated from the Service.asmx file and to perform source control changes like "Undo pending changes" you will have to make this operation on the Service.asmx file. Whatever change you make will cascade to the generated file.
If you are in doubt about the source control status of a file you can locate it in Source Control Explorer where you can perform operations on individual files even though the files are linked in Visual Studio. However, unless you know what you are doing I highly recommend that you stay in Visual Studio when working with files that are linked like this.
