From 7af8660355258052e9f4a161ebe16411ca23f467 Mon Sep 17 00:00:00 2001
From: "Kenneth Benzie (Benie)" <benie@infektor.net>
Date: Fri, 16 Aug 2019 21:58:38 +0100
Subject: [PATCH] Also set tmux navigation flag on FocusGained

Make using the `@vim$TMUX_PANE` window flag much more robust by
unsetting it every time the zsh prompt is drawn and setting it again
using a `FocusGained` `autocmd` in vim. This removes the need for the
hacky check for zsh in the conditional defined in the `in_vim` variable.
---
 autoload/tmux.vim   | 9 +++++++++
 plugin/autocmds.vim | 8 ++++----
 2 files changed, 13 insertions(+), 4 deletions(-)
 create mode 100644 autoload/tmux.vim

diff --git a/autoload/tmux.vim b/autoload/tmux.vim
new file mode 100644
index 0000000..910259e
--- /dev/null
+++ b/autoload/tmux.vim
@@ -0,0 +1,9 @@
+let s:tmux_option = '@vim'.substitute($TMUX_PANE, '%', '\\%', 'g')
+
+function! tmux#setNavigationFlag() abort
+  call system('tmux set-window-option '.s:tmux_option.' 1')
+endfunction
+
+function! tmux#unsetNavigationFlag() abort
+  call system('tmux set-window-option -u '.s:tmux_option)
+endfunction
diff --git a/plugin/autocmds.vim b/plugin/autocmds.vim
index 9f11c68..936af35 100644
--- a/plugin/autocmds.vim
+++ b/plugin/autocmds.vim
@@ -2,10 +2,10 @@ augroup benieAugroup
   autocmd!
 
   if $TMUX !=# ''
-    " Set tmux window option to detect when to change pane.
-    let s:tmux_option = '@vim'.substitute($TMUX_PANE, '%', '\\%', 'g')
-    call system('tmux set-window-option '.s:tmux_option.' 1')
-    au VimLeave * call system('tmux set-window-option -u '.s:tmux_option)
+    " [Un]set tmux window option to detect when to change pane.
+    call tmux#setNavigationFlag()
+    au FocusGained * call tmux#setNavigationFlag()
+    au VimLeave * call tmux#unsetNavigationFlag()
   endif
 
   " Reopening a file at last curson position