Hi All, I may be missing the obvious, but what are good strategies to understand the structure of existing code? Specifically, I'm trying to understand more of PharoJS to solve my own problems and eventually also to contribute back - but this is a general question. There is this one MOOC exercise: http://rmod-pharo-mooc.lille.inria.fr/MOOC/ Exercises/Exercises-Pillar/Pillar-Questions.pdf that helps, and reading tests and comments helps if they exist. But I often get trapped in drilling down a long call stack and opening many, many browser windows, a new one for every message send to a new class. While writing this it occured to me that I can use the debugger to follow a call stack by putting a breakpoint in the top level method, then stepping down using the debugger. There is also a MOOC lecture on that that I will look at again, http://rmod-pharo-mooc.lille.inria.fr/MOOC/Videos/W5/C019-W2S-VideosDebugger... . Any tips? I think I don't see the forest for the trees here I'm afraid :) thanks, Siemen