QWindow won't give up its active focus

Question

I'm trying to embed a CEF window to a qml window. It now looks like this. When embedding, I set the parent window of CEF window(QWindow for now) to the qml window, and modify its position. I can't think of a better solution. It looks nice though.

The problem is that the embeded QWindow won't give up its active focus. Once I clicked the embeded QWindow, activeFocusItem is set to null and no longer able to change

onActiveFocusItemChanged: {
    console.log(activeFocusItem)
}
// activeFocusItem changes whenever I click a item
qml: TextField_QMLTYPE_8(0x23363645080)
qml: TabButton_QMLTYPE_1(0x2336370a700)
qml: TabButton_QMLTYPE_1(0x233638b2710)
qml: TextField_QMLTYPE_8(0x23363645080)
qml: TabButton_QMLTYPE_1(0x2336370a700)
qml: TabButton_QMLTYPE_1(0x233638b2710)
// clicked the QWindow, it no longer changes
qml: null

code can be found here