The key that references the transition animation used when a view becomes visible, either as a result of being inserted into the visible view hierarchy or as a result of the view no longer being set as hidden .
Available in Mac OS X v10.5 and later.
Declaration Syntax Version Information- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)