clean up an error message in BufferManager (minor)

diff --git a/lib/sup/buffer.rb b/lib/sup/buffer.rb
index 17055a9726db555f4c6f52f57fbdc55c8600f797..f67623a5e9f633f4bffe843654f40e081d602e52 100644 (file)
--- a/lib/sup/buffer.rb
+++ b/lib/sup/buffer.rb
@@ -380,7 +380,7 @@ EOS
   end
 
   def kill_buffer buf
-    raise ArgumentError, "buffer not on stack: #{buf.inspect}" unless @buffers.member? buf
+    raise ArgumentError, "buffer not on stack: #{buf}: #{buf.title.inspect}" unless @buffers.member? buf
 
     buf.mode.cleanup
     @buffers.delete buf