This is how a "move" works:
- source initiates the drag & drop
- when successful, target copies the data from source
- when successful, source deletes the data
This is a nice clear understandable explanation.
I think it would not be bad to have something like that in the helpfile too.
I don't see what is so confusing about this. If you ignore the case of files, this is the only way this could work, as the target program cannot delete data in the source program.
Files are a rather common thing to be dragged.
Those are not usually part of an applications private data.
Yet, I consider them "original data".
So I was a little shocked to read about a drag source (not my app),
that would possibly take on, to remove(/delete) files (without my explicit consent).
Yes, just as you said: the target program cannot delete data in the source program.
I considered the thought, that it could or should be otherwise, allmost unthinkable,
therefore I did not see, why this should be mentioned in the helpfile,
unless it was refering to something rather unusuall (rather than unavoidable).
Who would ever asume, that the code in the target app would or should
bypass the code in the source application and do something in the other app