Execute FocusGained action for all windows

References #113.

plugin/signify.vim

@@ -33,10 +33,7 @@ augroup signify
   endif
 
   if get(g:, 'signify_update_on_focusgained') && !has('gui_win32')
-    autocmd FocusGained *
-          \ if exists('b:sy') |
-          \   call sy#start() |
-          \ endif
+    autocmd FocusGained * call s:refresh_windows()
   endif
 augroup END
 
@@ -91,6 +88,13 @@ function! s:save()
   endif
 endfunction
 
+" Function: refresh_windows {{{1
+function! s:refresh_windows() abort
+  let winnr = winnr()
+  windo if exists('b:sy') | call sy#start() | endif
+  execute winnr .'wincmd w'
+endfunction
+
 " Text object: ac / ic {{{1
 function! s:hunk_text_object(emptylines) abort
   if !exists('b:sy')