[MrGlenn]

When specifying new user interface behavior it is important to take into account the OS design. BlackBerry 10 for example has the following life cycle specification that application developers expect the OS to follow:
*IMG*
Applications are expected to exit from thumbnail (Active Frame) state. Any change to that would require some, maybe many or most, application developers to re-write a bunch of code.

Such a gesture as I mentioned doesn't need to be a new type of action at all! It could simply emulate "go into Active frame and immediately press X to close", like a virtual shortcut for 'Swipe up + press X'.
On Phys.keyboard devices it could be like 'long-press X+Space' for the same event.

It would (need to) be OS side and not change anything in the app processes really.
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Like I started saying, don't think it is a required feature, but I can definitely see the usefulness in some cases.


BlackBerry Q10 signed @ C0007CC89

[vbdwork]

It would (need to) be OS side and not change anything in the app processes really

Exactly. Swipe Up + Left can be just OS shortcut to Minimize + Close.