I was strollin' round Mhen'ga one say
In the very merry month of May
When there to my surprise
were a pair Doctors' Fine
When I was strolling round Mhen'ga one day!
I can't replicate this bug, but I can see where it could happen. I've made a fix for the next release that should block duplicate buttons if the button for the character already exists on the button tray. Same check will apply for Kattom as well.