I really like the "copy input to" and "Monitor for silence" and "Monitor for activity", but specifically the "copy input to". It allows one to type in one tab or window and choose which windows or tabs the input gets copied to. With this feature I can administer many machines at work at the same time. I know there are byobu and tmux, but I don't like these and they require time to learn the commands. I am willing to help on this code. I looked at the code and some of it I don't quite understand yet.
There is a fork on github that probably implements this feature. Author of the feature, Jerome Marty, sent a merge request in January 2011 (search for word 'activity' here https://mail.xfce.org/pipermail/xfce4-dev/2011-January/thread.html). Nick Schermer is assigned to merge it, but didn't do it yet.
Nick, if someone updated the patch so it starts working with master/HEAD, would you pull it? Or maybe you should delegate core-developer priviledges to some other xfce contributor. I know, that you do it in your free time. Or maybe shouldn't xfce have some fund-rising (there are some cool online social fund-raising sites, which allow lots of payment methods) to allow xfce core developers working on at-least half time?
Igor referenced this bugreport in commit 9892ee7d05fa2a29a49c9aaccffec5da05dfb785 Add "Copy Input" action https://git.xfce.org/apps/xfce4-terminal/commit?id=9892ee7d05fa2a29a49c9aaccffec5da05dfb785
Implemented.