If I send an e-mail To: someone, with the Reply-To: field set, claws will warn me that I am about to send e-mail to 2 recipients. That is not true - Reply-To isn't a recipient, so the warning is a little strange and should probably be modified not to count Reply-To fields.
Changes related to this bug have been committed. Please check latest Git and update the bug accordingly. You can also get the patch from: http://git.claws-mail.org/ ++ ChangeLog 2017-08-31 11:14:03.249452101 +0200 http://git.claws-mail.org/?p=claws.git;a=commitdiff;h=310095ab26517925750f6f50aa099fb593aba717 Merge: 7889558 9f24157 Author: Colin Leroy <colin@colino.net> Date: Thu Aug 31 11:14:02 2017 +0200 Merge branch 'master' of file:///home/git/claws http://git.claws-mail.org/?p=claws.git;a=commitdiff;h=9f24157d84365cfffeeff862898135e8894899a7 Author: Paul <paul@claws-mail.org> Date: Thu Aug 31 10:13:28 2017 +0100 fix bug 3886, '"About to send mail to 2 recipients" warning when one of them is Reply-To'