Alan Bowen schrieb am 22.04.2020 um 17:38:

When my component files were in the same directory as my component files, the line %! TeX root = prd_whatever allowed processing the component file from the component file. (I use TeXShop for this.)

The project structure has been changed: the component files are in a subdirectory of the directory that has the prd file. Now, %! TeX root = prd_whatever no longer works. (E.g., it cannot find the environment files called in the prd file.)

Is there a way to restore processing from the component file. My experiments are near to wearing out the “error” message/page.

What I get from your description is that your problem is editor related and has nothing to do with ConTeXt itself. What I found online is that TeXShop has to be told [1] to search for the main file in higher folder with % !TEX root = ../prd_whatever It is possible to do something similar with ConTeXt itself but then you get only a PDF with the current file and not the complete document. [1] TeXShop Tips & Tricks: https://herbs.github.io/ Wolfgang