I use ManicTime to keep track of time through unique tags, then enter the time along with notes into our ticket tracking system at the end of the week.

It would be extremely helpful to me to be able to mark a tag as reviewed and see visual feedback on it.

I'm currently changing the color of the tag to #ff0000 after entry, but there is margin for error here since a color in that range could pop up during tagging, and it would simply be less work for me to click twice.

Visually, the tag could automatically change to a reserved color, have a solid line through it, or become a bit transparent.