Tk-themed widgets are a separate collection of Tk widgets, which have a native look and feel, and their style can be highly customized using a specific API.

These classes are defined in the tkinter.ttk module. Apart from defining new widgets such as Treeview and Notebook, this module redefines the implementation of classic Tk widgets such as Button, Label, and Frame.

In this chapter, we will cover not only how to change our application Tk widgets for themed widgets, but also how to style them and use the new widget classes.

The themed Tk widget set was introduced in Tk 8.5, which should not be a problem since Python 3.6 installers let you include version 8.6 of the Tcl/Tk interpreter.

However, you can verify it on any platform by running python -m tkinter from the command line, which starts the following program that outputs the Tcl/Tk version: