diff --git a/lisp/icomplete.el b/lisp/icomplete.el
index 91bbb60013..543e451c5d 100644
--- a/lisp/icomplete.el
+++ b/lisp/icomplete.el
@@ -400,7 +400,7 @@ icomplete-mode
     (add-hook 'minibuffer-setup-hook #'icomplete-minibuffer-setup)))
 
 (defun icomplete--completion-table ()
-  (if (window-minibuffer-p) minibuffer-completion-table
+  (if (window-minibuffer-p) (and completing-minibuffer minibuffer-completion-table)
     (or (nth 2 completion-in-region--data)
 	(message "In %S (w=%S): %S"
 		 (current-buffer) (selected-window) (window-minibuffer-p)))))
diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index a0247d1fba..3ceb67733d 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -3826,6 +3826,8 @@ completing-read-function
   "The function called by `completing-read' to do its work.
 It should accept the same arguments as `completing-read'.")
 
+(defvar completing-minibuffer nil)
+
 (defun completing-read-default (prompt collection &optional predicate
                                        require-match initial-input
                                        hist def inherit-input-method)
@@ -3839,6 +3841,9 @@ completing-read-default
                 ;; `read-from-minibuffer' uses 1-based index.
                 (1+ (cdr initial-input)))))
 
+  (minibuffer-with-setup-hook
+      (lambda ()
+        (setq-local completing-minibuffer t))
     (let* ((minibuffer-completion-table collection)
            (minibuffer-completion-predicate predicate)
            ;; FIXME: Remove/rename this var, see the next one.
@@ -3862,7 +3867,7 @@ completing-read-default
                                          nil hist def inherit-input-method)))
       (when (and (equal result "") def)
         (setq result (if (consp def) (car def) def)))
-    result))
+      result)))
 
 ;; Miscellaneous