Split windows evenly when 'min-margins' parameter was set (Bug#44483)

* lisp/window.el (split-window): Make new window inherit any
'min-margins' parameter from WINDOW so that horizontal splits
reliably produce windows of same width (Bug#44483).

1 files changed, 7 insertions, 1 deletions

diff --git a/lisp/window.el b/lisp/window.el
index 48005fc93e0..ba56dedf046 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -5412,7 +5412,13 @@ frame.  The selected window is not changed by this function."
               (set-window-parameter (window-parent new) 'window-atom t))
             (set-window-parameter new 'window-atom t)))
 
-          ;; Sanitize sizes unless SIZE was specified.
+          ;; Make the new window inherit the `min-margins' parameter of
+          ;; WINDOW (Bug#44483).
+          (let ((min-margins (window-parameter window 'min-margins)))
+            (when min-margins
+              (set-window-parameter new 'min-margins min-margins)))
+
+          ;; Sanitize sizes unless SIZE was specified.
           (unless size
             (window--sanitize-window-sizes horizontal))