ファイル編集時にバッファに移る

こんなのどうでしょう？

$ git diff
diff --git a/autoload/vimshell/commands/vim.vim b/autoload/vimshell/commands/vim.vim
index cd507e5..f7ce8ee 100644
--- a/autoload/vimshell/commands/vim.vim
+++ b/autoload/vimshell/commands/vim.vim
@@ -69,7 +69,12 @@ function! s:command.execute(program, args, fd, other_info)"{{{
 
   lcd `=l:cwd`
 
-  wincmd p
+  if exists('g:vimshell_edit_no_split') && g:vimshell_edit_no_split
+    :on
+    :stopinsert
+  else
+    wincmd p
+  endif
 endfunction"}}}
 
 function! vimshell#commands#vim#define()

いろいろと駄目だった・・・

こう？

  if exists('g:vimshell_edit_no_split') && g:vimshell_edit_no_split
    wincmd p
    call append(expand('.'), g:vimshell_prompt)
    wincmd h
    :on
    :stopinsert
  else
    wincmd p
  endif