Add a tool that subscribes to editor changes

Hey everybody,

I would like to add a tool that displays an outline of the opened root node of my DSL.

I found and studies the following examples:

https://www.jetbrains.com/help/mps/howto-adding-additional-tools-aka-views.html
https://www.jetbrains.com/help/mps/dive-into-plugins-the-plantmps-plugin.html

The first examples contains a class “ToolSynchronizer”. I cannot find it but it looks quite interesting.

Is the source code somewhere available?

I found FileEditorManagerListener, studied ContextActionTool and some Mbeddr source code..
The first works but is not the listener I am looking for. The other two are quite large and look too complicated.

Isn’t there a simple solution

• to access the currently opened root node (to travers this node), and
• listen to content changes and selection changes?

Best
Sven