In `debug' don't try using window on inaccessible frame (Bug#17170).

* emacs-lisp/debug.el (debug): Don't try using "previous"
window when its not live or on an invisible frame (Bug#17170).

2 files changed, 9 insertions, 2 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index b28517f07ed..8f888e37b06 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2015-03-22  Martin Rudalics  <rudalics@gmx.at>
+
+        * emacs-lisp/debug.el (debug): Don't try using "previous" window
+        when its not live or on an invisible frame (Bug#17170).
+
 2015-03-21  Mario Lang  <mlang@delysid.org>
 
         * emacs-lisp/tabulated-list.el (tabulated-list-print): Only call
diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index dc0e666836e..38befeece45 100644
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -193,8 +193,10 @@ first will be printed into the backtrace buffer."
                debugger-buffer
                `((display-buffer-reuse-window
                   display-buffer-in-previous-window)
-                  . (,(when debugger-previous-window
-                        `(previous-window . ,debugger-previous-window)))))
+                 . (,(when (and (window-live-p debugger-previous-window)
+                                (frame-visible-p
+                                 (window-frame debugger-previous-window)))
+                       `(previous-window . ,debugger-previous-window)))))
               (setq debugger-window (selected-window))
               (if (eq debugger-previous-window debugger-window)
                   (when debugger-jumping-flag