What FlukeFan said is right for me although I have one small problem left:
it should be possible to add the same tasks, but when using the solution of FlukeFan, I get an exception:
Code:
a different object with the same identifier value was already associated with the session.
When using a bag, I don't get this exception, I've tried to use list in case of array, but that has the same result.
Is there a way to avoid this error?
Edit: solved, I check now if I had already added the object in the list and I just add the same object again, instead of making a new object.