I've also experienced this issue. In case this helps clarify:

I have a blueprint book, and I normally can shift+mousewheel to select the active blueprint. But as soon as I add enough blueprints to the book that the scrollbar appear, shift+mousewheel stops moving the green active blueprint square ...

merged threads, same topic
-- daniel34

TL;DR: Green, yellow, red lights on assemblers indicating their status - producing, waiting on output, waiting on input

This would be a quality of life addition to be able to get an overview of your different production areas by glancing at the assemblers ...

TL;DR Similar to the production/consumption menu for solid objects, fluids should either be added to this menu or a separate fluids production/consumption menu should be created.

Here's an example of when it would be useful. Right now I'm trying to figure out if I have a net surplus or deficit of ...