kiwanami/emacs-window-manager — pull request #45 by tkf (2013-01-16 18:24:24+00:00)
Title: Better error message from display-buffer

To check this patch, execute the following code
```lisp
(display-buffer "*no such buffer*")
```
Without this patch, it fails with a suspicious error. When
this patch is applied, it fails with a clean error message.