I’ use a Logitech M570 wireless trackball for ergonomic reasons, and it works perfectly on every other application (Win 11) - except in Comfyui the scroll wheel Zoom function doesn’t work right. One “click” of the scroll wheel causes the canvas to zoom to 1000X or so, making it very difficult to navigate. If the “Fit View” button is visible that will bring back a usable view and both the on-screen and hotkeys do work to zoom in/out as they should. But it would be a lot more convenient to be able to use the scroll wheel like most other software does. I’ve reduced the scroll increment from 3 to 1 but it didn’t make any difference. I had the same problem when I played with Comfyui on VastAI.
Google search turned up other mentions of this problem but I haven’t found a definitive answer and would certainly appreciate any suggestions as it drive me nuts 
Thanks!
Same issue, same windows 11, same M570 trackball here. - I wonder if it is the browser is part of the problem. When I open comfy in Firefox, I have this issue. DuckDuckgo presents differently
In Firefox, scroll wheel in zooms in like 500% per click, VERY fast. And scroll wheel out…….still zooms in. So you end up at like 600% as soon as you try to zoom, and then 1200% when you try to go the other way, it just compounds. Going to Settings and editing the zoom settings did not fix the issue.
When I opened it in duckduckgo browser I don’t have the issue (had an issue where it wouldn’t zoom out past 100% (do say 80%) but the changing the speed setting did fix that for some weird reason.
I’ve used the M570 trackballs on several PCs for many years without any issues with any browser or other software. The only time this has happened is with ComfyUI and the over-zooming problem occurred when I ran ComfyUI in the cloud using vast.ai as is is on my own computer. The only relief I’ve found is to set up the + and - keys on the number pad as hotkeys for Zoom In and Out, which is a pain but at least makes Comfy usable.
I’ve tried everything using the Logitech software but the M570 is not supported by their latest “Logi Options +” software so I can’t use it. I tried a Logitech “Track Man Wheel” wired trackball with the same scrollwheel but it has the same problem - instant zoom to full zoom.
If someone from the development team could please have a look at this it would be appreciated.
Welp, I don’t know what the magic word was but I must say THANK YOU to someone, because after months of not working, all of a sudden my M570 trackball scrollwheel will zoom in ComfyUI as it should!