tdf#130857 qt weld: Set msg dialog parent

If a parent is passed to `QtInstance::CreateMessageDialog`,
also set a parent for the `QMessageBox` that gets created
there:

If the passed parent is a native Qt one, use that one.
Otherwise, fall back to using the current active top-level
window, which is what usually makes most sense and is better
than having no parent at all.

With this change in place, the message dialog shown
when doing

1) start Writer
2) "File" -> "Properties" -> "Security" -> "Protect"
3) type 2 different passwords and confirm

is now modal and centered on top of the "Enter Password"
dialog on KDE Plasma Wayland when using the qt6 VCL plugin,
while it used to open at the top left of the screen and was
non-modal before.

The new behavior is in line with how it behaves for the
SAL_VCL_QT_NO_WELDED_WIDGETS=1 case.

Change-Id: Ibe95c2f0407edeba0fd9f76744bc087be7df6437
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/163362
Tested-by: Jenkins
Reviewed-by: Omkar Acharekar  <omkaracharekar12@gmail.com>
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

1 files changed, 15 insertions, 1 deletions

diff --git a/vcl/qt5/QtInstance.cxx b/vcl/qt5/QtInstance.cxx
index f2f8caa6b86a..6b3bd0cc301a 100644
--- a/vcl/qt5/QtInstance.cxx
+++ b/vcl/qt5/QtInstance.cxx
@@ -792,7 +792,21 @@ weld::MessageDialog* QtInstance::CreateMessageDialog(weld::Widget* pParent,
     }
     else
     {
-        QMessageBox* pMessageBox = new QMessageBox();
+        QWidget* pQtParent = nullptr;
+        if (pParent)
+        {
+            if (QtInstanceWidget* pQtInstanceWidget = dynamic_cast<QtInstanceWidget*>(pParent))
+            {
+                pQtParent = pQtInstanceWidget->getQWidget();
+            }
+            else
+            {
+                // the parent is not welded/not a native Qt widget; fall back to currently active window
+                pQtParent = QApplication::activeWindow();
+            }
+        }
+
+        QMessageBox* pMessageBox = new QMessageBox(pQtParent);
         pMessageBox->setText(toQString(rPrimaryMessage));
         pMessageBox->setIcon(vclMessageTypeToQtIcon(eMessageType));
         pMessageBox->setWindowTitle(vclMessageTypeToQtTitle(eMessageType));