I'm trying to mark as solved a topic with one single post. The poster edited his post right after posting to add his solution. Can I not mark it as solved? 

 

The first post in a topic cannot be marked as the solution at this time, I'm afraid.

Ok so actually it can be marked as the solution as long as there's at least one reply. So I have to reply something like "Thanks for posting your solution", then I can mark the first post as solved. 

Yes, that would be correct

Great, that works then. Thanks guys! 🙂