Mentions Widget - We would like option to clear selected Mentions once an update has a response

[#1]

We would like an option to clear selected Mentions once an update has a response.  

Currently the Mentions Widget retains mentions and it is hard to sort through them to determine what needs follow-up.  It would be nice to have the option to clear or hide selections Mentions once an update/reply has been made. 

[#2]

I would love something along the lines of a read/unread button on mentions and on the My Updates page - something where even if I've read the note, I can mark it as unread if I still need to do something with it. Similar to how I handle my emails.

[#3]

I think the ability to delete or read/unread mentions would be super helpful as someone who gets 10-20 a day based on my current role and the number of projects i'm @mentioned in on a daily basis.  Can this be updated?