Sliding panes [webOS 3.0]
After just a few minutes of using webOS 3.0 on the Touchpad, you will notice that many apps use sliding panes to allow the user to show or hide different areas of the app. The most obvious use of the sliding panes is in the email app, where you can choose between viewing your email accounts/folders, your list of messages in the selected folder, and/or the actual email message itself. These sliding panes are found in more than just the email app, as they are in many of the stock webOS 3.0 apps and apps "built for the touchpad" in the App Catalog.
Interacting with these panes is extremely easy. On the bottom-left of some panes, you will see an icon. This indicates that you have the option to move around the pane across the screen. To adjust your views, you can either drag that icon across the screen or you can just tap on it once. Both methods perform essentially the same task, although sometimes one method will adjust multiple panes at once, where there other requires multiple actuals to perform the same task.
In some instances, you can also tap on the header of the pane, as well. This will not work for all apps, or even all panes within an app. For example in the email app, only the middle pane (the list of your email messages) will accept a tap on the header while the others will not.