Hey,

Is it possible at all to add support for the modular vehicle and camper storages?

You can add any container you want by adding shortname in config file

I've tried this using, for example, "1module_storage" and "modular_car_1mod_storage" for the 1 slot modular car storage unit, however the button still fails to show in the UI on reloading the plugin.

Same result for "2module_camper" and "modular_car_camper_storage"

I think the issue you experienced is due to the "Check ownership" config option. Car modules don't have an owner, so the plugin will consider you to not be an owner, and therefore won't allow you to sort those containers.

I have been working on a new version of the plugin that resolves this issue by skipping ownership checks on any container that does not have an owner. I'm not sure if that's the best behavior of the plugin, considering it could cause issues with any plugin that spawn player deployables without an owner, but we'll see how it goes.

https://umod.org/community/sort-button/43739-sort-button-20-beta

Please try the beta and let me know whether that resolves your issue.