Difference between pending and draft

Hi

I have mentioned this before but I think it probably best if I ask some questions rather than say something is wrong.

I would like to know what is the difference between a pending post and a draft post? What circumstances lead to them being assigned to each area.

We are finding that a pending post can be opened in the backend no changes made, but closed and it ends up in the draft area.

Then when an author makes changes to a published article, it again ends up in drafts, but this is the real article, we had one like that today, we deleted the draft and the published post disappeared as well.

So how does easyblog decide where the posts go, I want to understand so we don't repeat any mistakes.

Thanks

Alex