DoNothing – Do Nothing. Used when the UIView is visible and should not do anything else.
Hide – Start hidden. Used when the UIView should be out of view at Start. This triggers an instant auto HIDE animation, thus the UIView hides in zero seconds.
PlayShowAnimation – Start by playing the SHOW animation. Used when the UIView should animate becoming visible at Start. This triggers and instant HIDE and then an automated SHOW animation immediately after that.