According to the guide, no. They'll remain open, you just won't see them. You'll have to go to the launcher or launch them from some event to bring them back.

WRT the browser, I'd like to see a mixed approach - ability to create multiple browsers in the multitasking view or at least ability to enter the browser application and see multitasking tabs. Multitasking page load is essential as well, which doesn't happen at the moment. That's my opinion, anyway.