tdf#164353 tdf#130857 qt weld: Keep extra msg dialog widget in place

Both, QMessageBox::setText, and
QMessageBox::setInformativeText call
QMessageBoxPrivate::setupLayout [1], and that one
deletes the QMessageBox's previous layout, creates
a new QGridLayout and sets that as the dialog's new
layout.

As a consequence, adding the widget that can hold
extra controls to the dialog's layout only once
by calling QtInstanceMessageDialog::addWidgetForExtraItems
from the QtInstanceMessageDialog ctor isn't sufficient,
but needs to be repeated each time the dialog layout
may have changed.
(Otherwise the widget is not contained in the layout,
and "randomly" placed in the dialog, so it can e.g.
overlap other UI elements in the dialog, see tdf#164353).

Therefore, rework QtInstanceMessageDialog::addWidgetForExtraItems
a bit,  rename it to QtInstanceMessageDialog::positionExtraControlsContainer
and call it also after updating texts.

[1] https://code.qt.io/cgit/qt/qtbase.git/tree/src/widgets/dialogs/qmessagebox.cpp#n290

Change-Id: Ib17b5867393a0694701c56b0ab74165021a8bc51
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/178726
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
(cherry picked from commit ffbe93aa93c0300dd4ff5f4d55dfb33e4c7a394d)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/178740

2 files changed, 18 insertions, 10 deletions

diff --git a/vcl/inc/qt5/QtInstanceMessageDialog.hxx b/vcl/inc/qt5/QtInstanceMessageDialog.hxx
index a775b8618050..f8430e98a609 100644
--- a/vcl/inc/qt5/QtInstanceMessageDialog.hxx
+++ b/vcl/inc/qt5/QtInstanceMessageDialog.hxx
@@ -43,7 +43,7 @@ public:
     virtual int run() override;
 
 private:
-    QWidget* addWidgetForExtraItems();
+    void positionExtraControlsContainer();
     virtual QPushButton* buttonForResponseCode(int nResponse);
 
 protected slots:
diff --git a/vcl/qt5/QtInstanceMessageDialog.cxx b/vcl/qt5/QtInstanceMessageDialog.cxx
index fb27aa544cb6..c9217609a9d5 100644
--- a/vcl/qt5/QtInstanceMessageDialog.cxx
+++ b/vcl/qt5/QtInstanceMessageDialog.cxx
@@ -22,8 +22,9 @@ QtInstanceMessageDialog::QtInstanceMessageDialog(QMessageBox* pMessageDialog)
 {
     assert(m_pMessageDialog);
 
-    m_pExtraControlsContainer = addWidgetForExtraItems();
-    assert(m_pExtraControlsContainer);
+    m_pExtraControlsContainer = new QWidget;
+    m_pExtraControlsContainer->setLayout(new QVBoxLayout);
+    positionExtraControlsContainer();
 }
 
 void QtInstanceMessageDialog::set_primary_text(const rtl::OUString& rText)
@@ -36,7 +37,10 @@ void QtInstanceMessageDialog::set_primary_text(const rtl::OUString& rText)
         return;
     }
 
+    // update text and ensure that extra controls are contained in the
+    // dialog's layout (new layout gets set when setting text)
     m_pMessageDialog->setText(toQString(rText));
+    positionExtraControlsContainer();
 }
 
 void QtInstanceMessageDialog::set_secondary_text(const rtl::OUString& rText)
@@ -49,7 +53,10 @@ void QtInstanceMessageDialog::set_secondary_text(const rtl::OUString& rText)
         return;
     }
 
+    // update text and ensure that extra controls are contained in the
+    // dialog's layout (new layout gets set when setting text)
     m_pMessageDialog->setInformativeText(toQString(rText));
+    positionExtraControlsContainer();
 }
 
 std::unique_ptr<weld::Container> QtInstanceMessageDialog::weld_message_area()
@@ -173,14 +180,19 @@ void QtInstanceMessageDialog::dialogFinished(int nResult)
 
     QtInstanceDialog::dialogFinished(nResponseCode);
 }
-
-QWidget* QtInstanceMessageDialog::addWidgetForExtraItems()
+void QtInstanceMessageDialog::positionExtraControlsContainer()
 {
+    assert(m_pExtraControlsContainer);
+
     // make use of implementation detail that QMessageBox uses QGridLayout for its layout
     // (logic here will need to be adjusted if that ever changes)
     QGridLayout* pDialogLayout = qobject_cast<QGridLayout*>(m_pMessageDialog->layout());
     assert(pDialogLayout && "QMessageBox has unexpected layout");
 
+    // no need to reposition if layout didn't change
+    if (pDialogLayout->indexOf(m_pExtraControlsContainer) >= 0)
+        return;
+
     // find last label
     const int nItemCount = pDialogLayout->count();
     int nLastLabelIndex = -1;
@@ -219,11 +231,7 @@ QWidget* QtInstanceMessageDialog::addWidgetForExtraItems()
     int nLabelColSpan = 0;
     pDialogLayout->getItemPosition(nLastLabelIndex, &nLabelRow, &nLabelCol, &nLabelRowSpan,
                                    &nLabelColSpan);
-    QWidget* pWidget = new QWidget;
-    pWidget->setLayout(new QVBoxLayout);
-    pDialogLayout->addWidget(pWidget, nLabelRow + 1, nLabelCol);
-
-    return pWidget;
+    pDialogLayout->addWidget(m_pExtraControlsContainer, nLabelRow + 1, nLabelCol);
 }
 
 QPushButton* QtInstanceMessageDialog::buttonForResponseCode(int nResponse)