Adapt my/centered-mode to split-root-window-right

(window-buffer window-to-split) returns nil in that case, because
window-to-split is the root of the "window tree" rather than a "leaf"
or "live" window with an actual buffer attached to it.

1 files changed, 6 insertions, 2 deletions

diff --git a/.emacs b/.emacs
index e052b91..1359c84 100644
--- a/.emacs
+++ b/.emacs
@@ -129,8 +129,12 @@
 (defvar-local my/centered-set-right-margin nil)
 
 (defun my/centered--undo-margins (&optional _size window-to-split)
-  (when (buffer-local-value 'my/centered-mode (window-buffer window-to-split))
-    (set-window-margins window-to-split nil nil)))
+  (let ((windows (if (frame-root-window-p window-to-split)
+                     (window-list)
+                   (list window-to-split))))
+    (dolist (w windows)
+      (when (buffer-local-value 'my/centered-mode (window-buffer w))
+        (set-window-margins w nil nil)))))
 
 (advice-add 'split-window-right :before 'my/centered--undo-margins)