'Modal' in terms of pageflow

[kooudy]

Hello,
in Seam's tutorial is

The stateful/stateless navigation distinction is quite similar to the traditional view of modal/modeless interaction. Now, Seam applications are not usually modal in the simple sense of the word - indeed, avoiding application modal behavior is one of the main reasons for having conversations! However, Seam applications can be, and often are, modal at the level of a particular conversation. It is well-known that modal behavior is something to avoid as much as possible; it is very difficult to predict the order in which your users are going to want to do things! However, there is no doubt that the stateful model has its place.

What does mean 'modal' there?

It is something in terms of accessibility lower window under above window,
I am little confused
thanks

[christian.bauer]

This is just Gavin going on about something...

The main point I think is that traditionally web applications only work in one browser window at a time, because all state is session-shared and several windows would produce conflicting updates. A workaround is to simulate several browser windows with modal dialogs. In Seam you use conversations for that, hence, the app works in several browser windows.

[kooudy]

thanks