Display an image when hover over an item in a Radio Button Group

You did not use any EVENT, either → onChange( ) , nor onClick( ) !
Additionaly you will recognize, that you also should use → blur( ) .

$w('#cb').onClick(()=>{
    if ($w('#cb').checked){
        $w('#cb').style.backgroundColor = "#E8E8E8"; $w('#cb').style.borderColor = "grey";
    } else {$w('#cb').style.borderColor = "red";}
    $w('#cb').blur();
});