When you check-in a code change using Team Explorer in Visual Studio, you can associate the check-in with one or more work items.
As shown in the snapshot below, the default option that appears against each work-item is ‘Resolve’. What this means is that when you check-in the changes, the work item status will be changed from Active to Closed. This also means that you can check-in code later to the same work item, but it’s status will not change.
Now, this can be really tricky if you are using TFS for ALM purposes. You would want to give a right picture to your Team Leads, Scrum Masters and Managers. So you would want to change the default to Associate. This can be done by a simple registry tweak
I am using Visual Studio 2013, hence the folder is
Value of Key ResolveAsDefaultCheckinAction needs to be set to False instead of True.
For other versions of Visual Studio, you will have to replace 12.0 with appropriate version in the folder name