The master records for the new task and the initial one are
                    computed as the following:
                  - If the initial or new task has only one source left, the
                            new task uses the source values for all attributes.
 
                  - If manual changes were performed on a given attribute,
                            these manual changes are kept for both the initial and the new
                            tasks.
 
                  - If one source was explicitly selected for a given
                            attribute, this source value is kept for the task to which it
                            belongs.
 
                  - Otherwise, the attribute is computed according to the
                            rules defined in the campaign.
 
               
               The selected source records are removed from the current
                        task and grouped in a new task which is added at the bottom of the list. Any
                        comments attached to the task to split will be kept for the initial task and
                        removed from the new one.