That button removed all the notifications when we were in beta. Something bad must have happened along the way that mucked it up in certain browsers. I have that on the development list to fix, right after the link thing in notifications. I even tried to grab another developer to do it so it would get done faster and the guy ran away crying. I guess we're stuck waiting for the regular guy to get to that part of the list.
Mine disappear from the chronological order when I used the drop down notification button in the black top band, choosing yours or others specific like/reply/comment etc. It would there-next place itself underneath the last unread notification. However, it isn't consistently for each notification which is why the reset option works wonders for me.
This post was edited by Benedict Arnold at October 28, 2016 12:42 AM MDT
Just Asking 