Modern App Wink
That is my suggested name for this feature.
I just wanted to share this video with you to document what I believe is an undocumented Modern App multitasking feature in Windows 8.1.
When I first saw this in the Windows 8.1 Preview I suspected it might just be a bug however, with it now being present in Windows 8.1 RTM it seems more like a UI feature as you work with multiple Modern Apps on one screen.
The video commentary explains everything.
I can also confirm that this behavior occurs on my Microsoft Surface RT which I am currently running the Windows 8.1 Release Preview on.
So have you seen this as well?
If you had a choice what would you call this feature?
Let me know in the comments and I will pick one of them to receive a 3GB SkyDrive Storage code courtesy of the SkyDrive team.