Scrolling through a vertical vim split that has a lot of multibyte utf8 characters causes horizontal overflows.

Mac OS X 10.11.6

Tried using both tmux 2.2 and HEAD (installed with homebrew)

$ locale
LANG="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_CTYPE="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_ALL="en_US.UTF-8"

$ echo $TERM
tmux-256color

Had same results with non-italics $TERM screen-256color.

Issue occurs in both Terminal.app and iTerm2.app and in both nvim and vim.

Running :redraw! (in vim) fixes the issue. Running refresh-client (in tmux) never fixes it.

The issue does not occur outside of tmux.