Filter by flag button

Hello,
I quite like the "filter by status" button which has been added some versions ago, but in some cases I have too many states in my workflow for this to be usable.
For most cases I think it would be useful to have a simpler option: a similar button in the top bar for quick access, but limited to filtering according to the "handled", "done", "closed" flags.
For me personally, this could even replace the current 'status' button, but depends on general usage of course. I do think making this feature simpler can make it useful in more use cases though.
Possibly a small but nice improvement

Regards