tag-order problem?

[Tanaka Akira <akr@xxxxxxxx>]

I found a problem as follows.

Z(2):akr@flux% Src/zsh -f
flux% echo $ZSH_VERSION 
4.0.1-pre-5
flux% bindkey -e; fpath=(Completion Completion/**/*(/)); autoload -U compinit; compinit -D
flux% zstyle '*' group-name ''
flux% zstyle '*:messages' format '%d'
flux% zstyle '*:descriptions' format '%d'
flux% zstyle ':completion:*' 'tag-order' '*:-non-cvs' '*'
flux% zstyle ':completion:*-non-cvs' 'ignored-patterns' '(*/|)CVS'
flux% compdef _tst tst
flux% _tst () { _arguments -s '-a-:x:' '-b' }
flux% tst -a<TAB>
x
option
-b

I think the option `-b' shouldn't completed here.
-- 
Tanaka Akira