When a user hits 'q' in a notmuch buffer, kill the buffer only if
there are no other windows currently showing it.
---
 emacs/notmuch-lib.el  | 13 +++++++++----
 emacs/notmuch-show.el |  2 +-
 emacs/notmuch-tree.el |  2 +-
 emacs/notmuch.el      |  4 ++--
 4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
index 1e166c6..fd25f7c 100644
--- a/emacs/notmuch-lib.el
+++ b/emacs/notmuch-lib.el
@@ -135,7 +135,7 @@ For example, if you wanted to remove an \"inbox\" tag and add an
 (defvar notmuch-common-keymap
   (let ((map (make-sparse-keymap)))
     (define-key map "?" 'notmuch-help)
-    (define-key map "q" 'notmuch-kill-this-buffer)
+    (define-key map "q" 'notmuch-bury-or-kill-this-buffer)
     (define-key map "s" 'notmuch-search)
     (define-key map "z" 'notmuch-tree)
     (define-key map "m" 'notmuch-mua-new-mail)
@@ -239,10 +239,15 @@ depending on the value of `notmuch-poll-script'."
 	(call-process notmuch-poll-script nil nil))
     (call-process notmuch-command nil nil nil "new")))
 
-(defun notmuch-kill-this-buffer ()
-  "Kill the current buffer."
+(defun notmuch-bury-or-kill-this-buffer ()
+  "Undisplay the current buffer.
+
+Bury the current buffer, unless there is only one window showing
+it, in which case it is killed."
   (interactive)
-  (kill-buffer (current-buffer)))
+  (if (> (length (get-buffer-window-list nil nil t)) 1)
+      (bury-buffer)
+    (kill-buffer)))
 
 (defun notmuch-documentation-first-line (symbol)
   "Return the first line of the documentation string for SYMBOL."
diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index a997482..6e03f1e 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -1956,7 +1956,7 @@ buffer. If PREVIOUS is non-nil, move to the previous item in the
 search results instead."
   (interactive "P")
   (let ((parent-buffer notmuch-show-parent-buffer))
-    (notmuch-kill-this-buffer)
+    (notmuch-bury-or-kill-this-buffer)
     (when (buffer-live-p parent-buffer)
       (switch-to-buffer parent-buffer)
       (and (if previous
diff --git a/emacs/notmuch-tree.el b/emacs/notmuch-tree.el
index e859cc2..8b6cd51 100644
--- a/emacs/notmuch-tree.el
+++ b/emacs/notmuch-tree.el
@@ -234,7 +234,7 @@ FUNC."
     ;; Override because we want to close message pane first.
     (define-key map [remap notmuch-help] (notmuch-tree-close-message-pane-and #'notmuch-help))
     ;; Override because we first close message pane and then close tree buffer.
-    (define-key map [remap notmuch-kill-this-buffer] 'notmuch-tree-quit)
+    (define-key map [remap notmuch-bury-or-kill-this-buffer] 'notmuch-tree-quit)
     ;; Override because we close message pane after the search query is entered.
     (define-key map [remap notmuch-search] 'notmuch-tree-to-search)
     ;; Override because we want to close message pane first.
diff --git a/emacs/notmuch.el b/emacs/notmuch.el
index b44a907..218486a 100644
--- a/emacs/notmuch.el
+++ b/emacs/notmuch.el
@@ -153,7 +153,7 @@ there will be called at other points of notmuch execution."
 (defvar notmuch-search-mode-map
   (let ((map (make-sparse-keymap)))
     (set-keymap-parent map notmuch-common-keymap)
-    (define-key map "x" 'notmuch-kill-this-buffer)
+    (define-key map "x" 'notmuch-bury-or-kill-this-buffer)
     (define-key map (kbd "<DEL>") 'notmuch-search-scroll-down)
     (define-key map "b" 'notmuch-search-scroll-down)
     (define-key map " " 'notmuch-search-scroll-up)
@@ -961,7 +961,7 @@ same relative position within the new buffer."
 	(oldest-first notmuch-search-oldest-first)
 	(target-thread (notmuch-search-find-thread-id 'bare))
 	(query notmuch-search-query-string))
-    (notmuch-kill-this-buffer)
+    (notmuch-bury-or-kill-this-buffer)
     (notmuch-search query oldest-first target-thread target-line)
     (goto-char (point-min))))
 
-- 
2.1.1