[OS X TeX] How to use BibDesk Completion

[Di Xiao]

Hi,

I notice there is a preference item in TexShop which enables BibDesk
Completion.  I searched the list and couldn't find a detailed
explanation on how to use it except the information that input manager
is no longer needed.  What's the hotkey to active this function?  Is
there other steps I need do to enable it?

I have a working latex file and a bib file.  Bibtex on the file
generates no problem.

Thanks,

Di