Thank you Bastien for your quick answer.
My understanding of the C-c C-x < command is that you restrict the agenda
view to one headline (i;e project in our case). How do you use the
:CATEGORY: property then ? Do you copy the project's name in that property
(or something shorter that makes you remember wich project it is) ?

Clément

2012/9/19 Bastien <bzg@altern.org>

> Hi Clément,
>
> Clément Mayet <cmayet@gmail.com> writes:
>
> > Given an action in a project, I would like to
> > see the action's project in the agenda view, and even better, to
> > order actions by project (or by context, then by project). Does
> > somebody have any hints on how to do that ?
>
> My top-level headlines are projects and they get a :CATEGORY: property.
>
> That way I can easily restrict agenda views to projects (C-c C-x < in
> the project's headline) or filter agenda items through projects (i.e.
> through category) by hitting `<' in the agenda view.
>
> HTH,
>
> --
>  Bastien
>