Screentip over button problem

Hi everyone,
I have a button that is an image that works perfectly but I’d like to put a kind of screentip or tooltip on it so when people hold over the button for a second the title of that button comes up.

My problem is that there seems to be some struggle going on between my code and the code that is already on buttons because the square that I’ve used just to test this flickers onto the screen along with the rollover.

Any help is very much appreciated!

Here’s my code:

emorals_btn.addEventListener(MouseEvent.MOUSE_OVER, emoralsHover);

function emoralsHover(event:Event):void
{
square_mc.x = mouseX;
square_mc.y = mouseY;
}