[Trac] are milestones just timepoints, or can they have dependencies?

Hi,

I'm playing with a shiny new trac installation (FreeBSD 5.2.1).
Things are working, and I'm trying to figure out how I'd like to use
it.

I have two questions about milestones:

 - What does it take for a milestone to be achieved?  Are there any
   dependencies on open bugs, or???  or is it just a matter of
   reaching the date?

 - I set up a milestone for Jul 18, 2004, and it looks like it was
   reached this at the start of the day.  If I want to mark something
   as done by the end of the day, it looks like I should use Jul 19,
   2004.  Does that make sense?

g.