Hi @HeyBaby and thanks for the post 👍🏼

One-off appointments (meaning that it isn't a recurring appointment) will be removed from your Calendar after you mark it as no-show.

If it were a recurring appointment, then the appointment will remain there even if you mark as no-show.

The ability to keep no-show appointments on the calendar is something we've heard about recently but it's not a feature yet.

The workaround a few sellers have suggested is to mark in the client notes that they were a no-show in order to keep track. 

Customizing the color to better identify specific appointments or actions is a popular request as well, so I'll share your interest with our Appointments team. Hopefully we're able to get something implemented in the near future that helps with all of this.