The :mod:`tkinter.simpledialog` dialogs were modernized to match the look and
feel of the native Tk dialogs.
:class:`!tkinter.simpledialog.SimpleDialog` and the
:func:`~tkinter.simpledialog.askinteger`,
:func:`~tkinter.simpledialog.askfloat` and
:func:`~tkinter.simpledialog.askstring` dialogs are now built from
the themed :mod:`tkinter.ttk` widgets instead of the classic :mod:`tkinter`
widgets; the :class:`!tkinter.simpledialog.Dialog` base class still defaults to
the classic widgets for compatibility.  Both :class:`!Dialog` and
:class:`!SimpleDialog` gained a *use_ttk*
parameter that selects between the classic Tk widgets and the themed ttk
widgets.  :class:`!SimpleDialog` also gained *bitmap* and *detail* parameters,
draws the standard icons with themed images in the ttk version, and accepts
mappings of button options as *buttons* entries, where an ``underline`` option
adds an :kbd:`Alt` key accelerator.
The font and wrap length of the message and the detail message are taken from
the Tk option database and can be overridden by the application.
The dialogs also follow the keyboard conventions of the Tk message box: the
default ring follows the keyboard focus, the Return key activates the focused
button, and the :class:`!Dialog` OK and Cancel buttons gained :kbd:`Alt` key
accelerators.
Several bugs were also fixed.
