Tkinter is often criticized for having a relatively inactive development community. This is true to a large extent. The documentation for Tkinter has remained a work in progress for many years now.

A large number of Tkinter extensions have appeared over the years, but most of them have not been under active development for a long time. 

Tkinter supporters refute this with the argument that Tkinter is a stable and mature technology that does not need frequent revisions, unlike some other GUI modules that are still being developed.