App UI is freezing after returning from Windows Lock screen.

zkrzysztoff7

Hi,
I'm trying to create something similar to sliding notification windows near system tray. Notifications data will be stored in a ListModel later on, so to maximize simplicity I used Repeater, Loader, and Window with appropriate flags (Loader was used because Repeater as a delegate requires an element derived from Item)

I noticed that the application can freeze, especially when the user is on the login screen (WinKey + L for quick access there) After returning from this screen, the application interface is frozen. Not always but often, I also noticed that this has some connection to the x/y coordinates when creating the notification window. If I set them somewhere off-screen, it freezes much more frequently after returning from the lock screen

I've prepared a minimalistic code fragment that frequently triggers the mentioned problem. On my laptop it's enough to go to the lock screen (WinKey + L) 2-3 times to freeze the UI. On much stronger PC its way more difficult to reproduce it at least for me.

import QtQuick

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

  Rectangle {
    id: animatedRect
    anchors.centerIn: parent
    width: 100; height: 100
    color: "#00FF00"

    NumberAnimation {
      target: animatedRect
      properties: "rotation"
      from: 0; to: 360
      running: true
      duration: 500
      loops: Animation.Infinite
    }
  }

  Timer {
    interval: 2000
    repeat: true
    running: true
    onTriggered: {
      repeater.model = 0
      repeater.model = 9
    }
  }

  Repeater {
    id: repeater
    model: 0
    delegate: Loader {
      sourceComponent: Window {
        x: (Screen.desktopAvailableWidth - 100) + index * 20
        y: (Screen.desktopAvailableHeight - 100) + index * 20
        flags: Qt.Window | Qt.Tool | Qt.FramelessWindowHint | Qt.WindowStaysOnTopHint
        visible: true
        Component.onCompleted: raise()

        Rectangle {
          anchors.fill: parent
          color: "#FFCCCC"
          border.color: "#000000"
          border.width: 2
        }
      }
    }
  }
}

I'm using Qt 6.9.2, on 6.8 this problem doesnt exist for some reason. Perhaps instead of using Repeater/Loader/Window and ListModel, I should dynamically load the component through Qt.createComponent. However, I would first like to understand why my method causes such problems and, if necessary, report a bug.

Does anyone have any ideas?