Thanks @Erel and I'm sorry, I hadn't thought to use the search for modules. I only tried clicking the small drop down at the end of the modules tabs but that only lists those actually present already.There is no issue here. The IDE opens up to 8 modules when it loads a project. There is no reason to open all modules. On large projects it can make a big difference in the performance.
Press Ctrl + E (modules tab) and go to whichever module you like. The IDE will open modules automatically when needed.