How to organize better the taxonomy-selection drop-down box in Views? I made a View to list a series of items. Each item has been assigned a Taxonomy term.

My taxonomy terms go like this:

--- Main1
----- Sub1
----- Sub2
--- Main2
----- Sub3
----- Sub4
----- Sub5


So there's a main category and inside other terms.

In my view, you can filter the entries to only display items for a certain category. But the dropdown menu is a mess. It goes like Sub3, Main2, Sub1, Sub5...

So, is there a way to organize it in a way it appears as I listed it above? And also, is it possible to give some kind of indentation for the  subterms in the dropdown? (So people can easily tell what is a main term and what's a sub-term).
You can use Hierarchical Select module to manage taxonomy terms in select list. 

See this discussion to implement hierarchical select with Views module : http://drupal.org/node/1170192