Describe the solution you'd like
Currently the creative inventory tabs and the item id's for Flan's Mod are haphazardly jumbled with no organization whatsoever. This makes it really difficult to find things quickly in creative mode with the creative tabs, which are at least sorted by content packs so that's a plus, or by NEI which sorts by item ID making it even more of a mess.
What I'm suggesting is to sort the item id's of flans mod the way they were in 1.7.10 and manually sort the item id's.

Describe alternatives you've considered
Sorting it in the source just for me because I'm OCD.

Additional context

Do you have any suggestions on what we order items by?
Perhaps sorting by content pack, then by item type, then by name?

Wowee that certainly was in depth.
For now, I've added a basic version of sorting by content pack, type, name. Unfortunately, as far as I can tell, there's no way to customise the sorting of items for a specific mod in NEI.

Basically like that. In depth description is this:

1. Gun Mod table then Vehicle table
2. Gun Boxes sorted by content pack, then sorted by display name forwards alphabetically, followed by the armor boxes sorted the same way
3. Parts sorted by content pack, then sorted by display name forwards alphabetically
4. Ammo sorted by content pack, then sorted by display name forwards alphabetically
5. Attachments sorted by content pack, then sorted by attachment type, then sorted by display name forwards alphabetically
6. Deployable ammo bag then medic bag
7. Grenades sorted by content pack, then sorted by display name forwards alphabetically
8. Mines and bear-trap sorted by content pack, then sorted by display name forwards alphabetically
9. Guns sorted by content pack, then sorted by display name forwards alphabetically
10. Melee weapons and shields sorted by content pack, then sorted by display name forwards alphabetically
11. Sentry
12. Artillery sorted by content pack, then sorted by display name forwards alphabetically
13. Tanks sorted by content pack, then sorted by display name forwards alphabetically
14. Jeeps sorted by content pack, then sorted by display name forwards alphabetically
15. Boats sorted by content pack, then sorted by display name forwards alphabetically
16. Helicopters sorted by content pack, then sorted by display name forwards alphabetically
17. Planes sorted by content pack, then sorted by display name forwards alphabetically
18. Mecha attachments sorted diamond first, then iron, then sorted by display name forwards alphabetically
19. Mecha upgrades sorted by upgrade type (slot position), then sorted by display name forwards alphabetically
20. Mechas sorted by display name forwards alphabetically
21. Explosive Remotes sorted by content pack, then sorted by display name forwards alphabetically
22. Blowtorch
23. Parachutes sorted by content pack, then sorted by display name forwards alphabetically
24. Healing items sorted by content pack, then sorted by display name forwards alphabetically
25. Armor sorted by content pack, then sorted by display name forwards alphabetically, then sorted helmet, body, legs, then boots

Team items you can just make them the last items in the mod, which would make it easier to see that Flans ends in NEI.

With NEI, it doesn't do anything except show the list of all items added by mods and minecraft. All you need to do is to tell forge how to sort the items in flans mod. Because if you have Flan's mod sorted, then NEI will have it sorted.

Please, do tell me how to "tell forge how to sort the items".

Tell it how to assign the numerical item id's.

Manually setting item IDs isn't a supported way of adding mod items anymore, that's how mod conflict hell happened.

I don't mean manually setting them, I mean telling forge the order to set the id's in.