Fix:widget position center

[jreydman]

Hello, i think it need fix center position

style: """
.contaiter
// FIX add this points
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
// FIX and remove this tip
    margin-top:34%
    margin-left:43%
// -----------

"""

Result