sticky scroll on sidebar and payloads

not a major requirement but it does help a lot to keep context when dealing with big collections of data; this is a feature popularized by xcode, vscode, some nvim plugins and it’s becoming more and more popular

https://learn.microsoft.com/en-us/visualstudio/ide/editor-sticky-scroll

from a quick check I didn’t see codemirror supporting this already, but I didn’t dig much into it, so it might be hard / not worth to work around