When a Dialog is hidden then it is possible that it does not reset the focus correctly if when it loses active focus it does the process again to hide the dialog

import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.5

ApplicationWindow {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    Rectangle {
        id: defaultItem
        anchors.fill: parent
        focus: true

        Keys.onLeftPressed: dialog1.visible = !dialog1.visible
        Keys.onRightPressed: dialog2.visible = !dialog2.visible
        Keys.onPressed: console.log("key pressed!")
    }

    Dialog {
        id: dialog1
        focus: true

        contentItem: Text {
            focus: true
            text: "dialog 1"
            Keys.forwardTo: [defaultItem]
        }
        onActiveFocusChanged: {
            console.log("activeFocus changed="+activeFocus+"-visible="+visible)
            if (!activeFocus)
                visible = false
        }
    }


    Dialog {
        id: dialog2
        x: 40
        focus: true

        contentItem: Text {
            focus: true
            text: "dialog 2"
            Keys.forwardTo: [defaultItem]
        }
    }
}