In normal everyday use of the TouchPad, Windows 8 may intepret the normal use of the TouchPad to be an application gesture intened to switch into the last used App, similar to pressing "Windows Button"+Tab or swiping in from the left side of the screen.
When this happens, an unintended application switch occurs.
If you are using the TouchPad and an application switch occurs when you did not intend for one to happen, then you may be unintentionally triggering the an edge swipe gesture. Ocassionally the gesture will also unintentionally trigger the Charms Bar or the Application Bar.
There are two solutions to this problem.
1. The tempoary solution is to use close any Modern UI (Metro) Aps prior to using desktop mode. This will prevent app switching because there is nothing to switch to.
2. The permanate solution is to disable the gesture.
To disable the gesture,
Press the Windows key or button and type "mouse"
You will now have a window that looks like this:
Select the "UltraNav" tab.
Make sure touch pad is enabled with advanced features.
Select the settings box from the TouchPad.
You will now be in the TouchPad Properties window.
Select the next to "Application Gestures" to reveal additional settings.
Then select "Edge Swipes"
You will now see a box to the right lablel "Swipe Gestures"
Uncheck "Enable Edge Swipes"
Press "OK" to close TouchPad Settings
Press "OK" to close Mouse Properties
Swipe has now been disabled on the TouchPad. You can still use the screen to Swipe.
These setting may be reset to defaults if Lenovo updates the TouchPad drivers. If you find yourself unintentionally triggering Swipes, just follow these directions again.