--- a/testing/web-platform/tests/webdriver/tests/contexts/maximize_window.py
+++ b/testing/web-platform/tests/webdriver/tests/contexts/maximize_window.py
@@ -244,27 +244,34 @@ def test_maximize_twice_is_idempotent(se
     assert_success(first_response)
     max_size = session.window.size
 
     second_response = maximize(session)
     assert_success(second_response)
     assert session.window.size == max_size
 
 
+"""
+TODO(ato): Implicit session start does not use configuration passed on
+from wptrunner.  This causes an exception.
+
+See https://bugzil.la/1398459.
+
 def test_maximize_when_resized_to_max_size(session):
     # Determine the largest available window size by first maximising
     # the window and getting the window rect dimensions.
     #
     # Then resize the window to the maximum available size.
     session.end()
     available = session.window.maximize()
     session.end()
 
-    session.window.size = (int(available["width"]), int(available["height"]))
+    session.window.size = available
 
     # In certain window managers a window extending to the full available
     # dimensions of the screen may not imply that the window is maximised,
     # since this is often a special state.  If a remote end expects a DOM
     # resize event, this may not fire if the window has already reached
     # its expected dimensions.
     before = session.window.size
     session.window.maximize()
     assert session.window.size == before
+"""