Try textSelectedColor style property. Please find more details on this property at the URL below.
Hope this helps.
Thank you, but that will change the color of the text and not the boldness.
I fear that i'll have to change my design, because the only solution i found googling it's a mess and i don't like it.
consider extending list class?
Sadly, i'm pretty noob to OO coding, ActionScript and Flex object hierarchy.
Do you think it would be worth the effort to learn extending flex classes?