Changes to collections are handled very differently in Observable’s web UI, and all variants are less than ideal:
/{user}?tab=collections: closing the settings modal of a collection (by saving or clicking “x”) results in a full content reload. This causes the scroll offset to change back to the top of page, so that editing multiple collections further down the list quickly becomes cumbersome./collection/{user}/{collection}: Removing a notebook from the current collection does not update the list of notebooks. The page has to be reloaded manually.