It would be great for quick factory upgrading if one could search for the machines with the selected module.

Especially useful if there is quite large amount of late game modules when the factory is already huge (see Space Exploration or Bob's modules) and going over all machines to even check whether they need module change would be pain in the ass.

Thanks for the suggestion, it would be straightforward to implement and I can see the use for it. However, I’m undecided as to whether it should be it’s own search mode or part of ‘storage’. ‘Storage’ doesn’t currently search assembling machines and modules in use are not conceptually being ‘stored’. On the other hand, adding a ‘Module’ search option that is only used very rarely would contribute to an overly complex interface and I really want it to be as simple as possible.

I’m also thinking of an option to search belts, pipes and inserters (called ‘Transport’?) which has similar issues: could be part of ‘Ground’ or its own thing.
Perhaps Module, Transport, Request and Signal should all be part of an ‘advanced’ mode togglable in user settings? Nicely reduces the first-time/occasional user overload while still having all options available to ‘power users’…

Done in v1.7.0.

I'm still considering how to improve the categorisation of the search options, but it seems ok as it is so I'm not too concerned.