Problem with presentation type inheritance (long)

Consider the following:

CL-USER 110 > (defclass b (a) nil)
#<STANDARD-CLASS A 205EEB64>

CL-USER 111 > (defclass b (a) nil)
#<STANDARD-CLASS B 205FD7A4>

CL-USER 114 > (clim:define-presentation-type a () :options (foo))
A

CL-USER 115 > (clim:presentation-type-specifier-p '((a) :foo t))
T

CL-USER 116 > (clim:presentation-type-specifier-p '((b) :foo t))
NIL

*** this was a surprise at first, but I quickly got over it and defined a ptype for b

CL-USER 117 > (clim:define-presentation-type b () )
B

CL-USER 118 > (clim:presentation-type-specifier-p '((b) :foo t))
NIL

*** now, this wasn't expected. the manual states the ptype for b will inherit from ptypes of the clos superclasses

CL-USER 119 > (clim:define-presentation-type b () :inherit-from 'a)
B

CL-USER 120 > (clim:presentation-type-specifier-p '((b) :foo t))
NIL

*** ok, so explicit inheritance didn't work either

CL-USER 121 > (clim:define-presentation-type b () :inherit-from 'a :options (foo))
B

CL-USER 122 > (clim:presentation-type-specifier-p '((b) :foo t))
NIL

So, I was surprised to find I need to explicitly define inheritance and options. Is this a bug?

Thanks,

Greg