diff --git a/modules/email/mu4e/config.el b/modules/email/mu4e/config.el
index 0481e723a..4fc3229ff 100644
--- a/modules/email/mu4e/config.el
+++ b/modules/email/mu4e/config.el
@@ -245,9 +245,12 @@ is non-nil."
   ;; so if the header view is entered from a narrow frame,
   ;; it's probably worth trying to expand it
   (defun +mu4e-widen-frame-maybe ()
-    "Expand the frame with if it's less than `+mu4e-min-header-frame-width'."
-    (when (< (frame-width) +mu4e-min-header-frame-width)
-      (set-frame-width (selected-frame) +mu4e-min-header-frame-width)))
+    "Expand the mu4e-headers containing frame's width to `+mu4e-min-header-frame-width'."
+    (dolist (frame (frame-list))
+      (when (and (string= (buffer-name (window-buffer (frame-selected-window frame)))
+                          mu4e-headers-buffer-name)
+                 (< (frame-width) +mu4e-min-header-frame-width))
+        (set-frame-width frame +mu4e-min-header-frame-width))))
   (add-hook 'mu4e-headers-mode-hook #'+mu4e-widen-frame-maybe)
 
   (when (fboundp 'imagemagick-register-types)