For example I google ManicTime and click on the ManicTime website. I can tag the latter activity based on its URL, but how do I tag the former as "ManicTime, ~googling"? Sometime the keyword does not go into the title, so I can't use it to autotag. Both the document and application timelines are the same, so I can't use append tag. The absorb tag just has the same color of the activities in between in the timeline, not a tag that I actually want.

This is also useful when you want an autotag to be prioritized, that is no other autotag shows up when it appears. Yes the "first applied autotag" option does this, but it affects on the whole system, hence is not really flexible in some cases.