Tkinter is a fact, not necessarily a feature.
Reorganize editor key bindings in a logical order
and remove those that do not work, at least on Windows.
Improve shell bindings list.
test_configdialog.HighPageTest.test_highlight_target_text_mouse fails
if a line of the Highlight tab text sample is not visible. If so, bbox()
in click_char() returns None and the unpacking iteration fails.
This occurred on a Devuan Linux system. Fix by moving the
'see character' call inside click_char, just before the bbox call.
Also, reduce the click_char calls to just one per tag name and
replace the other nested function with a dict comprehension.
Terry Jan Reedy
Ronald Oussoren