When a locked stack is alone in an area the renaming works just fine.
EDIT after some confusion: For anybody "accidently" reading this (like, for example saerching with the key word "rename"
) :
TO RENAME A STACK, PRESS ALT AND LEFT-CLICK THE NAME
(also notice that armies can't be renamed)

Wonder if it would work for a missed dinner date?
Don't think she will believe it... but try and report here the results