Factorio Forums

I would expect the scroll wheel to increase the sliders by 1 gradient, but it's all over the map depending on the scrollbar you scroll. For instance, the Evolution scroll bars all jump between 0 and their respective maximum values. Maximum expansion distance is especially wonky. The default is 7. Here's the pattern from scrolling the indicated direction one scroll gradient--up to 9, up to 10, down 8, up to 10, down to 9, down to 7, and so on.

Does the value/results change if you change your 'lines scrolled' setting in your OS? I'm wondering if the scroll value that the OS is sending is too high, thus causing this sort of behaviour.

If that's the case the solution is to either apply a division to the value given or to grab the scrolled value differently, I don't know what window API factorio uses but chances are there's two values you can grab ('pixels scrolled' and 'wheel motion' possibly).

edit; if using SDL, the values you get from sdlEvent.wheel.xy are absolute in wheel ticks.

Fixed for 0.15.11