diff --git a/modules/ui/popup/+hacks.el b/modules/ui/popup/+hacks.el
index 2140ed708..3819355c4 100644
--- a/modules/ui/popup/+hacks.el
+++ b/modules/ui/popup/+hacks.el
@@ -358,6 +358,15 @@ Ugh, such an ugly hack."
     (funcall fn function)))
 
 
+;;;###package undo-tree
+(defadvice! +popup--use-popup-window-for-undo-tree-visualizer-a (fn &rest args)
+  "TODO"
+  :around #'undo-tree-visualize
+  (if undo-tree-visualizer-diff
+      (apply fn args)
+    (letf! ((#'switch-to-buffer-other-window #'pop-to-buffer))
+      (apply fn args))))
+
 ;;;###package wgrep
 (progn
   ;; close the popup after you're done with a wgrep buffer