tdf#152979 qt: Re-add workaround for X11 modality change w/ hide/show

Essentially add back the workaround originally added in

commit e770bacc85a0eec96de77068d61b03f374b3cdec
Date:   Sun Jun 2 21:01:33 2019 +0000

Qt5 workaround modal change after show bug

but then dropped again in

commit 2dc6bdd1d5789ace0500cad90f5d2eb930888bb9
Date:   Wed Jun 5 17:39:45 2019 +0000

tdf#125692 SalObject always holds a SystemChildWindow

, since it turns out that it is still needed for other
use cases than the original one from tdf#125692, as the freeze
of the basic IDE dialog dialog preview described in tdf#152979.

The

qt.qpa.xcb: internal error:  void QXcbWindow::setNetWmStateOnUnmappedWindow() called on mapped window

issue mentioned there is apparently also worked around in
upstream Qt tests, s. this qtbase commit [1]:

commit 3714e51436eebb64873c58dc36cf89ef8f139f09
Author: Volker Hilsheimer <volker.hilsheimer@qt.io>
Date:   Mon Sep 20 13:44:26 2021 +0200

QWidgetWindow: Stabilize test on Xcb

Showing, hiding, and showing a window can result in the Xcb QPA plugin
warning about

qt.qpa.xcb: internal error:  void QXcbWindow::setNetWmStateOnUnmappedWindow()
called on mapped window

The point of the test is to verify that we get a paint event on a window
that is shown again after having been hidden, not to verify that async
windowing systems can handle a show/hide/show sequence. So wait for the
window being exposed before we hide it.

Pick-to: 6.2 5.15
Change-Id: If91a9926613645e78e332dacff34bd57e4034b6f
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

Decrease the sleep from the original 250 ms to 100 ms,
since tdf#152979 comment 14 mentions that this is enough.

[1] https://code.qt.io/cgit/qt/qtbase.git/commit/?id=3714e51436eebb64873c58dc36cf89ef8f139f09

Change-Id: I57ed520d0df85b7a3bcf47c2f9314754649482ee
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/149912
Tested-by: Jenkins
Reviewed-by: Rafael Lima <rafael.palma.lima@gmail.com>
(cherry picked from commit 574a5519e23e8ed50c54fb27587afb1b5b5c13c5)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/149883
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/vcl/qt5/QtFrame.cxx b/vcl/qt5/QtFrame.cxx
index 5517584b72d7..e580ea5df206 100644
--- a/vcl/qt5/QtFrame.cxx
+++ b/vcl/qt5/QtFrame.cxx
@@ -621,7 +621,16 @@ void QtFrame::SetModal(bool bModal)
 
         // modality change is only effective if the window is hidden
         if (bWasVisible)
+        {
             pChild->hide();
+            if (QGuiApplication::platformName() == "xcb")
+            {
+                SAL_WARN("vcl.qt", "SetModal called after Show - apply delay");
+                // tdf#152979 give QXcbConnection some time to avoid
+                // "qt.qpa.xcb: internal error:  void QXcbWindow::setNetWmStateOnUnmappedWindow() called on mapped window"
+                QThread::msleep(100);
+            }
+        }
 
         pChild->setWindowModality(bModal ? Qt::WindowModal : Qt::NonModal);