Qml 6 Bug on Window Restore from Task Bar

[Nan Feng]

Hi guys. I've found a serious QML issue. In Qt 6.6, 6.7, 6.8, other versions were not tested. Out of necessity, I need to implement a minimized borderless transparent form myself. Here's the code, it's very simple:

import QtQuick
import QtQuick.Controls.Basic

Window {
    id: _app
    width: 640
    height: 480
    visible: true
    title: ""
    flags: Qt.Window |Qt.FramelessWindowHint
    color: "#00000000"

Rectangle {
        width: 600
        height: 440
        anchors.centerIn: parent

Row{
            Button {
                text: "Min"
                onClicked: () => _app.showMinimized()
            }
        }
    }

}

Click the button to minimize the program, click the taskbar to restore, however, the question arises, what is in the upper left corner? Didn't I set the title? Why is this? I think this is a serious bug.

[mzimmers]

@Nan-Feng I'm not sure whether this qualifies as a bug or not, but if you remove the alpha channel from your Window color, it seems to work better.

color: "#000000"

or (better):

color: "transparent"

[JoeCFD]

@Nan-Feng This issue does not exist on Ubuntu 22.04. I tested it with 6.7.0

[Nan Feng]

@mzimmers Hi, the color can't be #000000 because I need transparent forms, so #00000000 and transparent are ok. But it will all appear in my screenshots.

[Nan Feng]

@Nan-Feng I didn't test Ubuntu and had this issue on Windows 10.

[Nan Feng]

@JoeCFD I tested 5.15.2 again on Windows 10 and found that it was very similar, that is, after the taskbar was restored, the cyan area would flash for a moment, specifically appear and disappear, less than a second before and after. This is persistent in Qt6,

[JoeCFD]

@Nan-Feng File a bug report to Qt with your test code. Could be OS related. If the issue exists in both Qt5 and 6, Qt guys may fix it quickly.

[Nan Feng]

@JoeCFD Thank you. Where to submit, can you send me an entrance?

[JoeCFD]

@Nan-Feng https://bugreports.qt.io/secure/Dashboard.jspa

[jds21 0]

For info, and for people arriving from a web search, the Qt bug that was filed is here: https://bugreports.qt.io/browse/QTBUG-125037