It's easy to reproduce if you move the 'with knobs' story on the top of the 'Button' group in examples/cra-kitchen-sink/src/stories/index.js:
gif

I'm not really sure, should we fix it on the side of knobs, tree, or both
Adding a written "+1":
We're seeing unusable levels of sluggishness in a large Storybook (~30 components, 40+ stories), with multiple stories that use knobs, after upgrading to v3.2.x. It's bad enough that I reverted back to the v3.1.x versions of @storybook/react and related dependencies.
I will attempt to investigate and further diagnose the underlying cause as time permits.
We're also seeing very slow rendering. Especially the encoding and decoding of knobs for the url is taking up a lot of time. It would be nice if it could be disabled.
You can change the sidebarAnimations to false with the options-addon. It will disable the tree animations.
https://github.com/storybooks/storybook/tree/master/addons/options
Hi everyone! Seems like there hasn't been much going on in this issue lately. If there are still questions, comments, or bugs, please feel free to continue the discussion. Unfortunately, we don't have time to get to every issue. We are always open to contributions so please send us a pull request if you would like to help. Inactive issues will be closed after 60 days. Thanks!
In my case, removing global withKnobs decorator helped a lot
Hi everyone! Seems like there hasn't been much going on in this issue lately. If there are still questions, comments, or bugs, please feel free to continue the discussion. Unfortunately, we don't have time to get to every issue. We are always open to contributions so please send us a pull request if you would like to help. Inactive issues will be closed after 60 days. Thanks!
Hey there, it's me again! I am going close this issue to help our maintainers focus on the current development roadmap instead. If the issue mentioned is still a concern, please open a new ticket and mention this old one. Cheers and thanks for using Storybook!
Did anyone else experience delayed knob state updates? Let's say I have a text knob and as I type, every 2 or 3 characters it will backtrack by 1. Makes it very frustrating to use. I am only trying to determine if this is because of knobs right now.
Most helpful comment
Adding a written "+1":
We're seeing unusable levels of sluggishness in a large Storybook (~30 components, 40+ stories), with multiple stories that use knobs, after upgrading to v3.2.x. It's bad enough that I reverted back to the v3.1.x versions of
@storybook/reactand related dependencies.I will attempt to investigate and further diagnose the underlying cause as time permits.