Frameless window on Windows has a returning titlebar after restoring from minimized state.

fear2137

Whenever I minimize my app with Window.showMinimized() and restore it, the window title gets displayed in a weird rectangle at 0,0
alt text
small reproduction project: https://www.mediafire.com/file/ozkurikrufvme8m/Example.zip/file

SGaist

Hi and welcome to devnet,

Which version of Qt ?
On which OS ?
If Linux:
Which distribution ?
Which desktop environment ?

fear2137

@SGaist Qt 6.6.0 Windows 11

ChrisW67

@fear2137 After correcting content/CMakeLists.txt in your example it configures, compiles, and runs without issue on Linux Qt 6.6.0 under KDE. The application main window stays frameless.
This is almost certainly going to be a Windows-ism. I have to get Qt 6.6 into a Windows environment to check.

Edit: Took a while to get everything in place (example is far from minimal): Qt 6.6.0, Windows 11, MingW tool chain. I see this on first launch:

and this after Minimize button, then restore:

Note the graphical artifact, top left. Not the symptom you claim, but not right either.

fear2137

@ChrisW67 this artifact is actually the titlebar I meant. Move screen01 down in y and you will see.

fear2137

To me it looks like Qt sets wrong flags in Windows, creating such window in cpp manually doesnt give this titlebar.

fear2137

does anyone know a fix to this?

Anton Beresnev

Do anyone can solve this problem?

Alxi11

Qt 6.7.0 has the same issue. I temporarily solved it with the following code.

// Main Window
Window{
    id: rootWindow
    property bool isMinimized: false
    onVisibilityChanged: {
        if(rootWindow.visibility === Window.Minimized){
            rootWindow.isMinimized = true
            rootWindow.flags = Qt.Window
        } else if(rootWindow.isMinimized === true){
            rootWindow.flags = Qt.Window | Qt.FramelessWindowHint | Qt.WindowSystemMenuHint | Qt.WindowMinMaxButtonsHint
            rootWindow.isMinimized = false
        }
    }
}

Stradlater

I solved this behavior by disabling WM_NCCALCSIZE message handling:

class WinEventFilter(QAbstractNativeEventFilter):
    def nativeEventFilter(self, eventType, message):
        if eventType == QByteArray(b"windows_generic_MSG"):
            msg = MSG.from_address(message.__int__())
            if msg.message == win32con.WM_NCCALCSIZE: 
                return True, 0
        return False, 0

fear2137

can we expect a official fix