New option for making Gnus window layouts atomic

* lisp/gnus/gnus-win.el (gnus-use-atomic-windows): New boolean
  customization option.
  (gnus-configure-windows): When removing old window layouts, check
  for and remove atomicity.
  (gnus-configure-windows): When gnus-use-atomic-windows is non-nil,
  make Gnus window layouts atomic.
* doc/misc/gnus.texi (Window Layout): Document.

1 files changed, 21 insertions, 0 deletions

diff --git a/lisp/gnus/gnus-win.el b/lisp/gnus/gnus-win.el
index e6906e99bb2..cc3141cf631 100644
--- a/lisp/gnus/gnus-win.el
+++ b/lisp/gnus/gnus-win.el
@@ -39,6 +39,11 @@
   :group 'gnus-windows
   :type 'boolean)
 
+(defcustom gnus-use-atomic-windows t
+  "If non-nil, Gnus' window compositions will be atomic."
+  :type 'boolean
+  :version "27.1")
+
 (defcustom gnus-window-min-width 2
   "Minimum width of Gnus buffers."
   :group 'gnus-windows
@@ -402,6 +407,15 @@ See the Gnus manual for an explanation of the syntax used.")
         (unless (gnus-buffer-live-p nntp-server-buffer)
           (nnheader-init-server-buffer))
 
+        ;; Remove all 'window-atom parameters, as we're going to blast
+        ;; and recreate the window layout.
+        (when (window-parameter nil 'window-atom)
+          (let ((root (window-atom-root)))
+            (walk-window-subtree
+             (lambda (win)
+               (set-window-parameter win 'window-atom nil))
+             root t)))
+
         ;; Either remove all windows or just remove all Gnus windows.
         (let ((frame (selected-frame)))
           (unwind-protect
@@ -423,6 +437,13 @@ See the Gnus manual for an explanation of the syntax used.")
           (set-buffer nntp-server-buffer)
           (gnus-configure-frame split)
           (run-hooks 'gnus-configure-windows-hook)
+
+          ;; If we're using atomic windows, and the current frame has
+          ;; multiple windows, make them atomic.
+          (when (and gnus-use-atomic-windows
+                     (window-parent (selected-window)))
+            (window-make-atom (window-parent (selected-window))))
+
           (when gnus-window-frame-focus
             (select-frame-set-input-focus
              (window-frame gnus-window-frame-focus)))))))))