"Copy To Right" feature saved file in /tmp instead of path, with git diffmode, when file does not exist in current commit

meld can be set as default difftool for git, which is nice.
Using meld with
$ git difftool HEAD~1 -d .
allows checking differences with previous commits.
Files which still exist in the current commit can be modified and "Copy To Right" works. But if the file does not exist in the current commit, the "Copy To Right" button does not show the expected behaviour.
It saves the file to a /tmp/git-difftool.7bOf2n/right/xxx directory but not to the expected path.