The System Preferences Dock "prefer tabs always" setting disables some
IDLE features.  Menus are a bit different than as described for Windows
and Linux.

A program that runs indefinitely can overfill memory.

Add a new subsection to the doc.

(This should have been done with the first PR for this issue.)

Two kind of mistakes:

1. Missed space. After concatenating there is no space between words.

2. Missed comma. Causes unintentional concatenating in a list of strings.

Topics include opening, title and status bar, .py* extension, and running.

Add a paragraph in "Help and preferences", "Help sources" subsection.

We now use git and backporting instead of hg and forward merging.

There is only one trivial change to idle.rst. Nearly all the changes to help.html are the elimination of chapter and section numbers on headers due to changes in the build system. help.py no longer requires header numbering.

A Windows build with _tkinter, tkinter, and idlelib
but without ctypes is unlikely but apparently possible.

Fix typos

Patch by Serhiy Storchaka (in PR #9642).

https://bugs.python.org/issue34548

* make CallTip and ToolTip sub-classes of a common abstract base class
* remove ListboxToolTip (unused and ugly)
* greatly increase test coverage
* tested on Windows, Linux and macOS

Some MacOS-tk combinations need .update_idletasks().
The call is both unneeded and innocuous on Linux and Windows.
Patch by Kevin Waltzer.

Added missing .grab_release() calls to all places where we call .grab_set().

Import pyshell first in htest to call SetProcessDpiAwareness on Windows
before tkinter.Tk() is called for the htest. Apparently, 'root.destroy()'
undoes a previous 'root = Tk()'. Since IDLE unittests always destroy roots,
a unittest before an htest does not require anything more to work right.
Since part of the purpose of human-viewed tests is to determine that
widgets look right, it is important that they look the same for testing
as when running IDLE.

These should have been included in PR 7836.

This avoids a failure in at least one case when running only a single
test method rather than all tests in the module.

The issue came up when testing the following on Windows 10 Pro 64-bit:
HighPageTest.test_highlight_target_text_mouse

In configdialog, the custom tabbedpages widget was replaced
by ttk.notebook several months ago.

Increases coverage by 44%.

Every other menudef key is the lowercase version of the
corresponding main menu entry (in this case, 'Window').

Match Window on the main menu and remove last plural module name.
Change imports, test, and attribute references to match new name.

The revised file compiles, runs, and tests OK. idle_test/README.txt
explains how to use it to create new IDLE test files.

Fix-up class name duplication in PR #7807. Combined effect is that
module calltips and its class CallTips are now calltip and Calltip.
In module calltip_w class CallTip is now CalltipWindow.

Improve consistency and appearance. Module idlelib.calltips is now calltip.
Class idlelib.calltip_w.CallTip is now Calltip.

Part 3 of 3, continuing PR #7689. This covers 14 idlelib modules and their tests,
rpc to zoomheight except for run (already done) and tooltip (being done separately).

Part 2 of 3.  Continues PR #7689, changeset ee5ef309.
Edit and add tests for 18 modules, help_about to replace and run.

Make it the same as when one runs 'python'.

Create a template for minimally testing a tkinter-using module by importing it and instantiating its class(es).  Add a test file for all non-startup IDLE modules.  Edit existing files and update coverage.  This is part 1 of 3, covering the 21 autocomplete to help modules and touching 33 idlelib files.