Mine

mc_clipbox._alpha = 30;
mc_listbox._alpha = 100;


function subeClipbox(){
//----------sube clipbox
	this.swapDepths(mc_listbox-0);
	
	// listbox transparente
	mc_listbox._alpha = 30;
		onEnterFrame = function() {
		  if (mc_listbox._alpha < 100) {
		  mc_listbox._alpha += 2  // velocidad transicion
   		}
	}
	
	// clipbox opaco
	mc_clipbox._alpha = 30;
		onEnterFrame = function() {
		  if (mc_clipbox._alpha < 100) {
		  mc_clipbox._alpha += 2  // velocidad transicion
		}
	}
		
}

function subeListbox(){
//----------sube listbox
	this.swapDepths(mc_clipbox-1);
	
	// clipbox transparente
	mc_clipbox._alpha = 30;
		onEnterFrame = function() {
		  if (mc_clipbox._alpha < 100) {
		  mc_clipbox._alpha += 2  // velocidad transicion
   		};
	};
	
	// listbox opaco
	mc_listbox._alpha = 30;
		onEnterFrame = function() {
		  if (mc_listbox._alpha < 100) {
		  mc_listbox._alpha += 2  // velocidad transicion
   		};
	};
}


mc_clipbox.depth1 = mc_clipbox.getDepth();
if(mc_clipbox.depth1 !== -16383){
	mc_clipbox.onRollOver = subeClipbox; 
	}

mc_listbox.depth2 = mc_listbox.getDepth();
if(mc_listbox.depth2 !== -16379){
	mc_listbox.onRollOver = subeListbox;
}


for (var i in this) {
    if (typeof (this[i]) == "movieclip") {
    trace("movie clip '"+this[i]._name+"' is at depth "+this[i].getDepth());
    }
}