Hello,
If you clone or copy a job from server 'A' to server 'B' the clone process keep the same id. As I understand from reading the different threads it is a 'feature' not a bug.
Therefore VisualCron never ask confirmation to do so and don't warn if the id already exists.
I tested this behaviour with the clone, copy and drag & drop commands. It always silently do the change.
Copy & past ask confirmation to proceed but don't check if the id exists.
Could you please consider to add this kind of check and ask confirmation to clone or create a new ID in place to silently replace it ?