Hi, thanks for your feedback. In a next release there will be an improvement in "Cached mode" preventing double runs and better indication of "loading" and "error" (if failed).
There are two prompts currently as you've rightly pointed out. The first one is to confirm the user action (this is because on most S3 buckets this operation may incur additional costs, e.g. if bucket has 100k files, user would pay at least for 100 list requests).
The second one is a way to notify user that rebuild has finished which we believe is useful, especially in rebuilds taking longer than a few seconds.
We could technically configure the first one: "Don't ask it anymore", but how would you like to get notified once rebuild has finished (second prompt)?
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Regarding your second feature request. We could add an option to persist last sort used in the cached mode accros all accounts. Would that work for you? (edited)