diff --git a/lisp/window.el b/lisp/window.el
index c750ea71ea..b46abd6ced 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -6231,6 +6231,17 @@ window-state-put
 	    (delete-window window))))
       (window--check frame))))
 
+(defun window-state-buffers (state)
+  "Return all buffers saved to the given window state STATE."
+  (let ((buffer (cadr (assq 'buffer state)))
+        (buffers (mapcan (lambda (item)
+                           (when (memq (car item) '(leaf vc hc))
+                             (window-state-buffers item)))
+                         (if (consp (car state)) (list (cdr state)) (cdr state)))))
+    (if buffer
+        (cons (get-buffer buffer) buffers)
+      buffers)))
+
 (defun window-swap-states (&optional window-1 window-2 size)
   "Swap the states of live windows WINDOW-1 and WINDOW-2.
 WINDOW-1 must specify a live window and defaults to the selected
diff --git a/lisp/tab-bar.el b/lisp/tab-bar.el
index 5eb332884c..9c8c38fb83 100644
--- a/lisp/tab-bar.el
+++ b/lisp/tab-bar.el
@@ -1284,6 +1284,12 @@ display-buffer-in-tab
               (tab-bar-rename-tab name))))
       (tab-bar-new-tab))))
 
+(defun tab-bar-buffer-visible-in-tabs-p (buffer)
+  "Return non-nil when BUFFER is visible in other tabs."
+  (seq-some (lambda (tab)
+              (memq buffer (window-state-buffers (cdr (assq 'ws tab)))))
+            (funcall tab-bar-tabs-function)))
+
 
 (defun switch-to-buffer-other-tab (buffer-or-name &optional norecord)
   "Switch to buffer BUFFER-OR-NAME in another tab.
diff --git a/lisp/desktop.el b/lisp/desktop.el
index 498f769bd3..6f45278218 100644
--- a/lisp/desktop.el
+++ b/lisp/desktop.el
@@ -946,7 +946,9 @@ desktop-outvar
 	      ")\n"))))
 
 ;; ----------------------------------------------------------------------------
-(defun desktop-save-buffer-p (filename bufname mode &rest _dummy)
+(defvar desktop-buffers-not-to-save-function nil)
+
+(defun desktop-save-buffer-p (filename bufname mode &rest rest)
   "Return t if buffer should have its state saved in the desktop file.
 FILENAME is the visited file name, BUFNAME is the buffer name, and
 MODE is the major mode.
@@ -970,6 +972,9 @@ desktop-save-buffer-p
 	     (and (null filename)
 		  (null dired-skip)  ; bug#5755
 		  (with-current-buffer bufname desktop-save-buffer)))
+	 (or (null desktop-buffers-not-to-save-function)
+	     (funcall desktop-buffers-not-to-save-function
+		      filename bufname mode rest))
 	 t)))
 
 ;; ----------------------------------------------------------------------------