diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index 34a2a13..f527dc8 100644
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -239,7 +239,8 @@ debug
 	      (pop-to-buffer
 	       debugger-buffer
 	       `((display-buffer-reuse-window
-		  display-buffer-in-previous-window)
+		  display-buffer-in-previous-window
+                  display-buffer-below-selected)
 		 . (,(when (and (window-live-p debugger-previous-window)
 				(frame-visible-p
 				 (window-frame debugger-previous-window)))