Sebastian, I did the following:
1. Took your version of ConcurrencyHandler.cs and plopped it into the Completed Solution from the concurrency Learning Unit in the product release;
2. Changed the namespace back to "UI";
3. Compiled the app successfully;
4. Set a breakpoint just inside the HandleConcurrencyException() method;
5. Ran two copies of the app (one by double-clicking the UI.exe executable);
6. Opened the Employee tab in both instances of the app to load the Employee data;
7. Changed Nancy Davolio's first name in the instance run by double-clicking UI.exe, and saved the change;
8. Changed Nancy's first name in the instance launched from inside Visual Studio, and attempted to save that, resulting in a concurrency exception;
9. At the breakpoint in HandleConcurrencyException, examined pException.EntitiesWithErrors[0] and found Nancy Davolio there.
So, I am unable to reproduce the problem.
Can you do the steps above with the *unchanged* Completed Solution with the Learning Unit and tell me if you get a different result?
Thanks,
Greg