bpo-43655: Tkinter and IDLE dialog windows are now recognized as dialogs by window managers on macOS and X Window (#25187)

diff --git a/Lib/tkinter/filedialog.py b/Lib/tkinter/filedialog.py
index 3ed93eb..600d0bd 100644
--- a/Lib/tkinter/filedialog.py
+++ b/Lib/tkinter/filedialog.py
@@ -24,6 +24,7 @@
 )
 from tkinter.dialog import Dialog
 from tkinter import commondialog
+from tkinter.simpledialog import _setup_dialog
 
 
 dialogstates = {}
@@ -62,6 +63,7 @@ def __init__(self, master, title=None):
         self.top = Toplevel(master)
         self.top.title(title)
         self.top.iconname(title)
+        _setup_dialog(self.top)
 
         self.botframe = Frame(self.top)
         self.botframe.pack(side=BOTTOM, fill=X)