"~" after file names ? other file-system questions

[Vincent]

Almost all my "*.wkp" or "*.pat" files in my Library folders are doubled and followed by a tilde, even when Usine is not running. Most of them are older than the "pure" one - and smaller. Not temp files, right?
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1
Could you explain me their use? I did not find explanations in the Doc.
I feel it has something to do with "Save as" and a misunderstanding of mine... as if the current edited patch and the "saved as" were not the same (the "save as" philosophy can change from a soft to another).
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2
Could that explain disconcerting surprises I had sometimes when reopening a workspace (or a patch) and not finding it exactly like I saved it last time? Very strange! I'm not that kind of PC user doing such mistakes!
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3
Has it also something to do with the workspace that loads at startup and witch is never exactly the one I was working on previous session?

Thanks!

[senso]

hello,
the ~ is the old version:
when you save a patch, Usine rename the old one into something like xxxx.wkp~ or zzzz.pat~ helpfull in case of mistake.

1) the "save as" is just save the file under a new name.
2) normally, it should be exactly the same. I've never noticed such a bug. ..but we never know.
3) I don't think so...