Thanks, cool find. I used it in my mod too.

I have experience in GUI development and I can say - I couldn't come up with anything better.

Thanks again!

i might be able to improve it just a little bit, was forced to touch some gui stuff for recent mods

which mod of yours plays with this?

https://mods.factorio.com/mod/RailLogisticsDispatcher

The dispatcher itself under the hood is a decider combinator. And to form output signals, I hid a constant combinator connected to the dispatcher's output. And with your discovery, this became unnecessary - I can form the output signal using the combinator itself. I have already fix it locally, I am testing it now. I will release it soon.

ah neat, clever behind the scenes tricks are always nice