First of all, I'm not sure if this has been reported before or not. I searched for it and didn't find anything. Also, I'm not sure if this is intended or not, forgive me if I'm wrong.
Problem Details:
Each forum and subforum has an osu! logo on the left to see if there are unread message or not. Ok, if you mark a whole forum (with its subforums) as read, the logo will turn grey. If there is any new message and you read it, the logo will not be turned to grey anymore, even if you don't have any unread messages. It will just be turned to grey again if you click the "Mark all read" button.
It happens with forums and Subforums.
Here you can see the button grey because I don't have any read messages:
Then, it turns pink because there is a new message:
After reading that message, I don't have any unread message but the button will still be pink:
Problem Details:
Each forum and subforum has an osu! logo on the left to see if there are unread message or not. Ok, if you mark a whole forum (with its subforums) as read, the logo will turn grey. If there is any new message and you read it, the logo will not be turned to grey anymore, even if you don't have any unread messages. It will just be turned to grey again if you click the "Mark all read" button.
It happens with forums and Subforums.
Here you can see the button grey because I don't have any read messages:
Then, it turns pink because there is a new message:
After reading that message, I don't have any unread message but the button will still be pink: