Because Ultracopier have extensive control, check every thing before move/copy to be sure of the integrity of the copy. Old Supercopier, Windows, other copier have lot of missing control, that's mean: can show the copy succes but in reality the file is corrupted. But the windows copy/move too by pass the user right (it should not) to be more accessible the the basic user.
Same problem as the resume on hard shutdown, the list can be corrupted, and introduce lot of similar problem, add complexity in the program (more bug, more difficult to solve the bug). And windows don't send me the Ctrl + Z action... then I can't undo (I don't have the event). And the list write mean less hdd performance.
In reality "Quit" just hide the window, the transfer stop but need few time to close the file. Undo can't be instant (like move) because on partition to another partition you need do the reverse transfer.
I'm according, if I have easy and safe ways to do it, I can do it, but I have not.
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