Question: Unexpected behavior of "remove"

Hi all

I'm fighting agaist this situation:

ccc:= sin(x);

S:= select(has,ccc,x)
     sin(x)
R:=remove(has,ccc,x);                                  
     sin()

what's that??? why doesn't it aswer 1 or " " istead?

How am I supposed to trust in the remove procedure? What should I do in order to have a variable with the x-dependence and another with all the motiplicative constants (or variables)? I mean: it doesn't seem too much asking a buit-in procedure that decompose a monomial in the terms matching a variable, and the others, even if a single term is present.

Additionally, in my opinion, the "select/remove" help page should be modified: this point:

A typical application that uses select and remove is to split the factors of a product, e, into those which depend on a variable x and those which do not (that is, constants). This can be accomplished by using  v := select(has,e,x); followed by   c := remove(has, e, x). It is more efficient, however, to use  v, c := selectremove(has, e, x). Do not try to compute  e c := -    v. 

is clearly valid only if there is a constant. It should be overlined, i think.

Tks

Salvo