Each day more close to smalltalk ;)
Let me elaborate on your comment for other readers though. Smalltalk is a programming language in which an entire (graphical and audio) environment called Squeak was built. Smalltalk's dynamic nature and the nature of its global namespace (for classes and their methods) means that class and methods can be modified from within the environment at any time (and any future calls will use the new method). This is the part that make it similar to tkui (or perhaps rather tkui similar to Squeak).
I remember Squeak having a tree (I forget the name) but don't remember if it was easy to edit with it directly.
I've sort of noticed the opposite sentiment -- the things that software images can do (sharable consistent environment, dependencies and tools corralled into one place instead of polluting the host) are considered to be upsides of using docker containers for development; but people seem to prefer using languages and tools they already know inside docker, instead of learning Smalltalk.