I accumulate about a new autotag rule a day. Therefore, at the end of my timekeeping period (e.g., August 15), while I might have copied autotags for August 1-14 to their respective tag timelines on a semi-regular basis, there are usually at least some rules that I've created towards the end of the timekeeping period that need to be applied to the earlier days of the timekeeping period.

My current workaround is to step back through each day of the timekeeping period in "Show only untagged activities" view, scan the autotag line for some color (meaning an autotag that still hasn't been copied to the tag timeline) and then press "Copy autotags to tags" ("Fill only untagged time" (rarely do I click otherwise)).

It would be nice to have a "Copy autotags to tags" button that permitted copying for multiple dates.