func_button #

Player use policy - choose an algorithm of detecting if player can use a button.
Custom sounds (including locked and unlocked sounds and sentences).
New parameter Use Type to set the passed use type to a button’s target (On or Off).
Trigger on return - target to trigger when button is back. This is for moveable buttons.
Trigger before move/rotate - target to trigger when button has been activated but hasn’t moved (or rotated for func_rot_button) yet. This is for moveable buttons.
Delay before toggling again - delay before the button with Toggle spawnflag can be pressed again (by default there’s no delay).
Target on locked - target to trigger if button is used when locked by master. Delay between such usages is 2 seconds.

Direct use only - require a direct non-occluded view of entity in order to use it (superceded by a new parameter Player use policy)
New flag Player Can't Use to disallow player use (button still can be called via other entities). Note: if you just want a brush with a switchable texture use func_wall.