Hi Martin,
We did test doing the paste functionality that way ("open ended based on the copied region") but found surprisingly that a lot of users complained because the region they thought they were pasting into was not the same size as the region they were copying from
Ergo, we kept the "select the exact region to paste into" so there were no surprises such as copying over something that the user did not want copied over.
We do have some tasks to do that should make the process easier, though. Stay tuned
ttfn,
Sherry