 
 	_calculateConstraints: (bounds) ->
 
+		if not bounds
+			return constraints = 
+				minX: Infinity
+				maxX: Infinity
+				minY: Infinity
+				maxY: Infinity
+
 		constraints = 
 			minX: Utils.frameGetMinX(bounds)
 			maxX: Utils.frameGetMaxX(bounds)

	@define "vertical", @simpleProperty "vertical", true, true

	@define "momentumVelocityMultiplier", @simpleProperty "momentumVelocityMultiplier", 800, true, _.isNumber

	@define "constraints",
		get: -> @_constraints

				y: @_lockDirectionEnabledY

			# @_propagateEvents = false if @multipleDraggables

	_resetLockDirection: ->
		@_lockDirectionEnabledX = false
