[Interest] Qt-6.10.2 Widgets - Qt::CustomizeWindowHint Is Broken on Windows

[coroberti]

Dear Wladimir,
Additionally, removing the patch you mentioned and
*Qt::WindowSystemMenuHint* :

Qt::Window | Qt::CustomizeWindowHint | Qt::WindowTitleHint |
 Qt::WindowStaysOnTopHint | *Qt::WindowSystemMenuHint*
together with
this->setWindowIcon(QIcon(appIconPath));

indeed adds the icon from the left as well as inactive Close control from
the right - this is an unwanted addition:

[image: image.png]

Thanks,

Kind regards,
Robert Iakobashvili
............................


On Mon, Feb 9, 2026 at 5:12 PM coroberti <coroberti at gmail.com> wrote:

> Wladimir,
> Volker says the following:
> "The system menu is one of those things; so without
> Qt::WindowSystemMenuHint or any other button (which might imply a system
> menu with the corresponding entry)
> I’d expect no window menu. *And without window menu, there’s no space for
> an icon*."
>
> You are breaking the behavior of Qt-4, next Qt-5, next Qt-6 till Qt-6.10
> and even worse, you are doing that in the mid of Qt-6.
>
> Could you please send these considerations to Volker, and at least
> postpone it to the next major Qt-7?
> Thanks.
>
> As a minor request, please kindly try not to top-post in your next
> messages since it forces me to top-post as well.
> Thank you in advance!
>
> Kind regards,
> Robert Iakobashvili
> ............................
>
>
> On Mon, Feb 9, 2026 at 4:54 PM Wladimir Leuschner <
> wladimir.leuschner at qt.io> wrote:
>
>> Hi,
>>
>> The patch that caused the regression is now reverted and in 6.10.3 the
>> old behaviour should be there again. Regarding the Window Icon when using
>> Qt::CustomizeWindowHint, there is an answer by Volker Hilsheimer in the
>> comments of https://qt-project.atlassian.net/browse/QTBUG-143832.
>>
>> Best regards,
>>
>> Wladimir Leuschner
>>
>> Public
>> ------------------------------
>> *Von:* coroberti <coroberti at gmail.com>
>> *Gesendet:* Freitag, 6. Februar 2026 08:00
>> *An:* Wladimir Leuschner <wladimir.leuschner at qt.io>; Qt Interest <
>> interest at qt-project.org>
>> *Betreff:* Re: [Interest] Qt-6.10.2 Widgets - Qt::CustomizeWindowHint Is
>> Broken on Windows
>>
>> Sie erhalten nicht häufig E-Mails von coroberti at gmail.com. Erfahren Sie,
>> warum dies wichtig ist <https://aka.ms/LearnAboutSenderIdentification>
>> On Tue, Feb 3, 2026 at 8:45 PM coroberti <coroberti at gmail.com> wrote:
>>
>> On Tue, Feb 3, 2026 at 7:02 PM Wladimir Leuschner <
>> wladimir.leuschner at qt.io> wrote:
>>
>>
>> thank you for reporting the bug. This behaviour is indeed a regression
>> and was introduced with
>> https://codereview.qt-project.org/c/qt/qtbase/+/619145 to 6.10.2 and
>> 6.11beta2 by me. Sorry for that. A bug report related to the issue seems
>> already created with https://qt-project.atlassian.net/browse/QTBUG-143832.
>> In case you have additions to the report you are welcome to comment on the
>> bugtracker.
>> Best regards,
>> Wladimir Leuschner
>>
>>
>> ------------------------------
>> *Von:* Interest <interest-bounces at qt-project.org> im Auftrag von
>> coroberti <coroberti at gmail.com>
>> *Gesendet:* Dienstag, 3. Februar 2026 11:35
>> *An:* Qt Interest <interest at qt-project.org>
>> *Betreff:* [Interest] Qt-6.10.2 Widgets - Qt::CustomizeWindowHint Is
>> Broken on Windows
>>
>> Hi,
>> Qt::CustomizeWindowHint was removing the three right-angle controls from
>> a window for many years,
>> but it seems to be now broken for Qt-6.10 at least on Windows.
>>
>>  Qt::Window| Qt::WindowTitleHint |  Qt::CustomizeWindowHint
>> Thus, we were getting a window with a title-bar but without the 3
>> controls from the right side.
>>
>> Status for now is:
>> [image: image.png]
>>
>> All controls are present and maximize is even active.
>>
>> The attempts to remove the controls by getting flags and zeroing the bit
>> for flags
>> like & ~ individual hint - all failed.
>>
>> The only workaround that works 4me is adding the
>> flag Qt::MSWindowsFixedSizeDialogHint - the consequence is that the image
>> icon gets out.
>> You can compile versus the Qt-6.10.2 and easily reproduce the break by
>> using the *Windows Flags Example*.
>>
>> https://doc.qt.io/archives/qt-5.15/qtwidgets-widgets-windowflags-example.html
>> and the code:
>>
>> https://code.qt.io/cgit/qt/qtbase.git/tree/examples/widgets/widgets/windowflags?h=5.15
>>
>> Am I the only one to see it or most people do not advance to the latest
>> Qt?
>>
>>
>> Hi,
>> Even if it were reversed, there is still an issue with presentation of
>> the left angle Windows icon on the window.
>> Perhaps the issue is the general for Qt-6.10 series.
>>
>> When the flag  Qt::CustomizeWindowHint is set, the small windows icon is
>> not shown
>> unless one adds ad least a single control like flags |=
>> Qt::WindowCloseButtonHint
>>
>> It is just ignored:
>> this->setWindowIcon(QIcon(appIconPath));
>>
>> Thanks,
>> Robert
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.qt-project.org/pipermail/interest/attachments/20260209/4616b0cc/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 1599 bytes
Desc: not available
URL: <http://lists.qt-project.org/pipermail/interest/attachments/20260209/4616b0cc/attachment-0002.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 1319 bytes
Desc: not available
URL: <http://lists.qt-project.org/pipermail/interest/attachments/20260209/4616b0cc/attachment-0003.png>