Issue #27620: Mark the default action button as the default.
diff --git a/Lib/idlelib/query.py b/Lib/idlelib/query.py
index c4e2891..c806c6b 100644
--- a/Lib/idlelib/query.py
+++ b/Lib/idlelib/query.py
@@ -83,7 +83,7 @@
         self.entry.focus_set()
 
         buttons = Frame(self)
-        self.button_ok = Button(buttons, text='Ok',
+        self.button_ok = Button(buttons, text='Ok', default='active',
                 width=8, command=self.ok)
         self.button_cancel = Button(buttons, text='Cancel',
                 width=8, command=self.cancel)