Did some test - maybe it brings some idea to Don?
Must test with IZArc, no WinRAR here...
While testing, I watch the temp folder used by IZArc with XY in active pane.
(Sometimes I must refresh manually - sometimes not!?)
- left-drag file from IZArc to XY (in 2nd pane) "copies" the file, but creates a copy in IZArc-temp.
- left-drag file from IZArc to WE copies the file, and even deletes the old copy in IZArc-temp!
- left-drag a duplicate to WE: you see file created in temp, and dialog asks "replace or cancel".
-- on replace it replaces, and the temp file is deleted
-- on cancel it terminates, but temp-file remains!
- left-drag a duplicate to XY:
-- "replace or cancel", and *after refresh* file is shown in temp,
-- after replace and after cancel the temp-file remains.
- right-drag to XY: "not allowed"!
- right drag to WE: temp-file appears, dialog "move or cancel"
-- on move it's moved, i.e. copied and deleted
-- on cancel it remains in temp!
From my point of view the dialog is misleading: I *copy* from IZArc to WE - and normally don't see that in the background a *move* from temp to WE takes place. But I don't know if the dialog is initiated from IZArc or from XY/WE. (IZArc should know better, XY/WE not.)
To summarize:
XY never deletes temp,
WE always deletes, *if* the operation is completed successfully.
The dialog on right-move (in WE) seems(!) to show that IZArc requests a move

*Then* the temp should be deleted...
...and this would possibly explain, why WE does *not* delete, if the operation is canceled! (As no move takes place.)