Before I update the collapsible menu into AS3, I realised that I was dissatisfied with the animation's motion.  The tweening was done using the well known method

	x -=(x-dx)/speed

Although smooth I found it unreliable at times (try clicking on many buttons real fast and see the menu mess up).  Of course I could use Robert Penners easing equations, but I find them too cookie cutter. I went back to the linear easing equations I had posted and implemented them in the collapsable menu.  The results are far better and I can custom control the movement equation ... notice the bounce in the animation :

	var pos = startH +  distanceH + (-distanceH*Math.cos(t*Math.PI));