IDLE shell uses wrong namespace for completions

GitHub fields:

assignee = 'https://github.com/terryjreedy'
closed_at = None
created_at = <Date 2019-08-11.11:17:08.862>
labels = ['3.8', 'expert-IDLE', 'type-bug', '3.7', '3.9']
title = 'IDLE shell uses wrong namespace for completions'
updated_at = <Date 2019-08-14.03:02:56.017>
user = 'https://github.com/taleinat'

bugs.python.org fields:

activity = <Date 2019-08-14.03:02:56.017>
actor = 'terry.reedy'
assignee = 'terry.reedy'
closed = False
closed_date = None
closer = None
components = ['IDLE']
creation = <Date 2019-08-11.11:17:08.862>
creator = 'taleinat'
dependencies = []
files = []
hgrepos = []
issue_num = 37821
keywords = ['patch']
message_count = 5.0
messages = ['349386', '349387', '349437', '349557', '349634']
nosy_count = 2.0
nosy_names = ['terry.reedy', 'taleinat']
pr_nums = ['15207']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue37821'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']