Application/themes/atomik kills calendar function

I wanted to create my own page_not_found page for Atomik theme and so I created application/themes/atomik/page_not_found.php and set up the code for the page.

Then I got reports that the calendars had stopped showing events, though the event list was still working fine.

Investigation showed that themes/atomik/main.js was coming up ‘not found’.

It did exist in concrete/themes/atomik though not in application/themes/atomik so I assume it was trying to load it from the application area.

Did I do something wrong or is there a problem with concrete?

maybe you need to really clone the theme, see this doc: How to clone and customize Atomik theme :: Concrete CMS

but before going on production, test it and wait if some concrete’s dev more advised than me has another suggestion

So it seems that themes can’t be modified in the same way blocks can.
Does the documentation mention this anywhere?

I think it’s kind of a cascading thing - if you’re overriding thing that makes subsequent calls to other things, you’re going to have to override those things too.