Change text color in a Symbol?

Hello

I have a Symbol (a button) that consists of a Text and an Ellipse.

I want to change the color of the text when hovering over the Symbol:

So I added this code to 'mouseover' of the Symbol:

sym.getSymbol("mySymbol").$("myText").css("color","red");

but nothing happens. What can be the reason? When I replace 'color' with 'background-color' it works, but that's not what I want.

Jürg

(version 2015.0)