(Within the standard review process) I received review comments on a paper, one of the reviewers, say A, waived his anonymity in the review submitted to the journal (I know A personally). Now, A made some suggestions (essentially about some way of using software developed by students of A) which do not work (suggested feature does not exist). Should I
- write an email to A directly asking about clarifications on how to use the software as he suggested, at the risk of the handling editor feeling like I went behind his back
- write this email, but include the handling editor as CC:, at the risk of A feeling like I would "belittle" him "in front of" the editor, or
- mention in the response that the feature was not implemented in the suggested software, citing documentation / error messages