Fork’s now back to using a single probe (less stress, more consistent performance both in Chrome and FF), and the probing interval can be increased. If there are no objections I’ll be merging it back into the main notebook tomorrow.
Edit: Merged and added some sliders to play with.
Okay, thanks again! I just set a permanent offset of 50px for now to avoid having the observable header hide any content.
I just published some updates to Sticky Positioning / Fabian Iwand / Observable. The most important change is that there’s no need for a probe element anymore. To obtain fresh intersectionRects it’s sufficient to repeatedly call observe() / unobserve() on the <html> element.