Rachel Jiang over at Windows Phone blog provided an insider look at some of the navigation improvements coming in the "Mang" Windows 7 Phone--including ones related to multitasking.
Reviewing the basics
There're two hardware buttons on every Windows Phone for getting around: Start and Back. Pressing Start takes you to the Start screen, populated by Live Tiles that can be pinned, removed, and reordered to suit your tastes. Start is both a launch pad for favorite apps and your personal space. It's a big part of what makes your WP unique.
Flicking left takes you to the App list, where all your apps are ordered alphabetically. The App list is consistent and predictable. You can reliably find an app (even when it's infrequently used) by name.
Finally, there's the Back button, which pretty much does what it says: takes you back to the place you came from or left off.
Finding apps faster
"Tapping a header in the People Hub today opens the quick jump menu (left), which can whisk you to a specific section of your contacts list. In Mango (right), we're adding the same feature and a search option to the App list.
In the People Hub we use search and a quick jump menu to help you find contacts quickly. Ultimately, we decided that approach was the best solution for the App list, too.
Although there is one slight difference. When implementing the quick jump option, we wanted to balance function with aesthetics. If you don't own many apps, the feature doesn't make much sense, since the alphabet headers artificially lengthen the App list, creating gaps that make it feel sparse and unappealing. Hence, you'll only see the headers when you've installed at least 45 apps.
o added a search option. If you've used it in People, it works like you probably expect, filtering the list of apps as you type. If you don't find the app you were searching for, we provide a convenient link to get it from Marketplace by tapping Search Marketplace," stated Jiang.
Say hello to the "task switcher." "In Mango, pressing and holding the Back button on your phone calls up the task switcher, which makes it easy to quickly pick up where you left off.
When you do, you'll see a set of "cards" that represent the last 5 things you did or apps you used, arranged in the order you used them. (My team's nickname for this feature is "visual back".) These cards remind you what you were doing so you can pick right back up again. This is efficient multitasking.
Flick left or right and tap on a card to resume right from where you left off. The task switcher is designed to be fast and predictable," Jiang said.
"One design problem we pondered at length was how many cards to show. We wanted the experience to be intuitive and require minimal effort. Five seemed like a good balance. Having only a small number of cards ensures that the task switcher is predictable."
[Source: Windows Phone blog]