IDLE completions are currently implemented in two files: autocomplete.py and autocomplete_w.py.  (Before 3.6, these were AutoComplete.py and AutoCompleteWindow.py.) The first handles 'open' events, decideds whether to open a window, and gathers possible completions.  The second open a popup and works with the sorted list of possible completions. There are several tracker issues already.#15786 Code completion problems with mouse and <return>.      These lead to freezes on on Mac.  Severity: bad; prioriy: high.#16198 Tabbing in string brings up completion when it should not.#17238 Enhance import statement completion.#18766 Add completions for un-imported modules (by importing).#18903 File completions are case sensitive, should not be on Windows.#21261 Complete dictionary keys.#22554 Popup window for names also.#27099 Convert autocomplete to normal feature, along with other 'extensions'.  Add delay to current tab.  Negative delay should disable auto-popups.#27534 Move objects needed by run to run.py and import from there.There are more that are not on the tracker.  Patches may be attached here or to new issues.A. UsePEP8 style.  1.'return None' when there are non-None returns. 2. Docstrings for all functions.B. Merge autocomplete_w into autocomplete.  This was anticipated in the renaming.#27534 should be done first if possible, or soon after.C. Refactor.  1#27534.  2. Put list and scrollbar in Frame?  For future single-window IDLE?  This might make testing easier. 3. Anything else making tests easier.D. Make completions work for number literals ("1 .") as well a string literals ("'a'.").E?. Make completions work with Entry as well as Multicall wrapping text?  Need use case first.  Load Modules may need own code.Question: Why does 'dooneevent' appear in 2.x code and not 3.x code?Tests: The currently only for a subset of autocomplete methods.  There are none for the buggy window.First, a patch for A.1, return None.

Add dependencies.  Last two,#27099 and#27534 involve multiple files and should be removed from this autocomplete list when autocomplete part is done.

New changeset1ec47de72538 by Terry Jan Reedy in branch 'default':Issue#27609: Explicitly return None when there are other returns.https://hg.python.org/cpython/rev/1ec47de72538

I just partly fixed#16198.  Anything more depends on a careful definition of desired behavior that turns out to be different from current behavior.

Add 27675.  If open quote is ' or '', actions (character key or box selection with up or down arrow) after first are not colored.  ' and ''' do not complete, when needed, nor close.

#30666 Add completion tests#30667 Revise completion doc#15786 and additional discussion of completion behaviorTab in opened box should and usually completes, but sometimes not.  I don't have a consistent example.

#30632 autocomplete tests#30666 autocomplete_w tests

In re-verifying#27675, the color bug seems to be gone.  The completion bug is still here, at least on Windows.It would be good to sort the issues by whether they appear to affect autocomplete.py or autocomplete_w.py or both.

#37765 Include keywords in ''(__main__) list.###### Annotate completion list, at least as an option, with 'keyword' or class, possibly prefixed with 'built-in', so 'built-in function', 'function', and so on.#37766 revise fetch_completions, add htest

38943 Autocomplete box sometimes does not show on Ubuntu.38944 Excape key should close completion box.

40892 Use prefixes from rlcompleter.  Compute constant once.

Normally, tab completion works for attributes (after '.' and a possible prefix) and files (after os.sep and a possible prefix).  Unique matches to prefixes are immediately selected, as for undotted module names.  After changing the completion wait time and before restarting, this is disabled and tab adds spaces instead.  This need a new issue and fix.

The removed post duplicates the content of#37766.  Another bug is reported and will be fixed there.