Menu animation - following mouse

I have a symbol that moves onto a button along the x axis when the mouse goes over the button.
The buttons have the following code (or similair, depending on where it is on the stage) attatched:

on (rollOver) {
yTargetMC = 358;

(MC being the instance name of the symbol, and 358 being the center of that specific button)

The actions for the symbol reads as follows:

onClipEvent (enterFrame) {
yMC = getProperty(_root.MC, _x);
moveMC = _root.yTargetMC - yMC;
setProperty(_root.MC, _x, yMC + (moveMC/10));

The symbol starts off the stage and zooms in when the mouse goes over a button. In the very first scene the symbol is told to go to one of the buttons as a starting point. Other scenes ommit this code in my hope that the symbol would just stay where it is scene after scene. It doesn’t.

After playing around with it I have had to keep the symbol starting off stage at the begining of every scene, otherwise it does nothing for that whole scene; it just stays put, even when the mouse goes over a button.

So currently everytime you click on a menu button, the symbol comes flying in from the side. I want it to stay where the user left it between scenes.