Button border missing

Hi,

i have a alloy window with some buttons:

<Alloy>
    <Window class="container" backgroundColor="#555" backgroundImage="/Fondo App.jpg" onOpen="PosicionaBotones" >
 
        <Button id="BProg1" top="8%" left="1%" width="15.4%" height="11%" onClick="SacoLunes">Lu</Button>
        <Button id="BProg2" top="19%" left="1%" width="15.4%" height="11%" onClick="SacoMartes">Ma</Button>
        <Button id="BProg3" top="30%" left="1%" width="15.4%" height="11%" onClick="SacoMiercoles">Mi</Button>
        <Button id="BProg4" top="41%" left="1%" width="15.4%" height="11%" onClick="SacoJueves">Ju</Button>
        <Button id="BProg5" top="52%" left="1%" width="15.4%" height="11%" onClick="SacoViernes">Vi</Button>
        <Button id="BProg6" top="63%" left="1%" width="15.4%" height="11%" onClick="SacoSabado">Sa</Button>
        <Button id="BProg7" top="74%" left="1%" width="15.4%" height="11%" onClick="SacoDomingo">Do</Button>
 
    </Window>
</Alloy>

The buttons are transparent and when i load the screen from another window i can see the border of the button with the text "Lu", "Ma", ...

But if i push the button 4 or any button, then execute

function SacoJueves(){
    $.BProg4.setOpacity(0.3);
    setTimeout(function () {
        $.BProg4.setOpacity(1);
    }, 200);
}

and now the border of the button is missing, only see the text "Lu", "Ma", ...

I've tried with $.BProg4.show(), $.BProg4.setOpacity(1), and other but i can't see the entire button.

How i can find my border??

I'm use Android with titanium 3.4.0.GA

Thanks