NBA tag not working properly in Minecraft 1.6

ok well i don't know if this is a bug or not but i found that when i tried using the NBA tag to name a mob in creative AND survival... nothing happened they didn't get named as no gui screen popped up or anything so i thought it might be a bug or something and i did try left clicking and right clicking each time and still... nothing happened not even A GUI screen so yeah hope this gets worked out and eventually solved