Re-introduce activity overview behaviour from 1.x to version 2+

Created by: ghost

My Hamster use case it to track time spent and report those times and tasks into time sheet software required by the company I work for.

In version 2, the tracking has seemingly gotten a bit worse. I can no longer see decimal values for the time spend on each bar, and the activities themselves are no longer showing, just the categories and the tags. I can also no longer select a single category, tag or task and have Hamster adjust the other bars to show related items.

I would love it if this was reintroduced, as the new Hamster otherwise looks much better, but version 2 destroys my use case.