[3.6]bpo-27922: Stop gui flash from idle_test.test_parenmatch (#2171) (#2172)

For unknown reasons, this does not work when running leak tests.
(cherry picked from commit 049cf2bb44038351e1b2eed4fc7b1b522329e550)

diff --git a/Lib/idlelib/idle_test/test_parenmatch.py b/Lib/idlelib/idle_test/test_parenmatch.py
index 051f7eac2dce0634c2d501abecbb53d27377334a..b5fd0d1c69e4f1e47382c5756f94365c17f8e4fd 100644 (file)
--- a/Lib/idlelib/idle_test/test_parenmatch.py
+++ b/Lib/idlelib/idle_test/test_parenmatch.py
@@ -24,6 +24,7 @@ class ParenMatchTest(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.root = Tk()
+        cls.root.withdraw()
         cls.text = Text(cls.root)
         cls.editwin = DummyEditwin(cls.text)
         cls.editwin.text_frame = Mock()