I have the external clipboard option enabled:
$ tmux show-options -g -s set-clipboard
set-clipboard external
And I'm using Kitty terminal with tmux in SSH.
When I highlight text with the mouse or use <C-B>[, the contents get copied to my system clipboard just fine, and I can paste it back into tmux using <C-B>]. However, when I pipe as follows:
$ echo -n "Hello World" | tmux loadb -
The contents are correct for <C-B>], i.e. when I paste within tmux, but my system clipboard is not updated. I can't figure out why that is, shouldn't it be the same behavior?