When you go to the New posts/topics page, you would usually see posts that you have not opened since your last visit on the site and some of these posts have been marked as solved.
It would be nice to have a Dismiss Solved button (pretty self explanatory).
Edit:
Along with that, a dismiss button beside each post would also be a great addition
If it’s not specifically about the Developer Forum (i.e. Roblox-related or something no other Discourse forum does/has) I recommend posting on the Discourse meta. This doesn’t seem like something we should implement since it’s so generic, I recommend asking around on the categories related to Discourse Solved Plugin - plugin - Discourse Meta.