Question: why this doesn't work?
```

QPushButton{
    height: 50px;
    width: 50px;
    color: black;
    font: bold;
    font-size: 8px;
    image: url(":/images/Boton_OFF.png");
}

QPushButton:checked {
    image: url(":/images/Boton_ON.png");
}

QPushButton:pressed {
    image: url(":/images/Boton_ON.png");
}´´´
while this works?
´´´
ActionButton {
    color: black;
    font: bold;
    font-size: 8px;
    image: url(":/images/Boton_OFF.png");
}

ActionButton:checked {
    image: url(":/images/Boton_ON.png");
}

ActionButton:pressed {
    image: url(":/images/Boton_ON.png");
}´´´