3 files changed, 12 insertions, 4 deletions
diff --git a/src/widgets/dialogs/qmessagebox.cpp b/src/widgets/dialogs/qmessagebox.cpp
index f9d58e4d906..acb63c4aa9b 100644
--- a/src/widgets/dialogs/qmessagebox.cpp
+++ b/src/widgets/dialogs/qmessagebox.cpp
@@ -562,6 +562,10 @@ void QMessageBoxPrivate::helperClicked(QPlatformDialogHelper::StandardButton hel
     and \l{QMessageBox::standardButtons} {standard buttons} for
     accepting a user response.
 
+    While the parent parameter is optional, specifying it gives a hint
+    to the window manager, which can then take care of positioning, and
+    maintain a proper stacking order of the dialog window.
+
     Two APIs for using QMessageBox are provided, the property-based
     API, and the static functions. Calling one of the static functions
     is the simpler approach, but it is less flexible than using the
diff --git a/src/widgets/doc/snippets/code/src_gui_dialogs_qmessagebox.cpp b/src/widgets/doc/snippets/code/src_gui_dialogs_qmessagebox.cpp
index ebc07025ec0..062e2e5142a 100644
--- a/src/widgets/doc/snippets/code/src_gui_dialogs_qmessagebox.cpp
+++ b/src/widgets/doc/snippets/code/src_gui_dialogs_qmessagebox.cpp
@@ -12,7 +12,7 @@ int ret = QMessageBox::warning(this, tr("My Application"),
 
 
 //! [2]
-QMessageBox msgBox;
+QMessageBox msgBox(this);
 QPushButton *connectButton = msgBox.addButton(tr("Connect"), QMessageBox::ActionRole);
 QPushButton *abortButton = msgBox.addButton(QMessageBox::Abort);
 
@@ -53,13 +53,13 @@ int main(int argc, char *argv[])
 //! [4]
 
 //! [5]
-QMessageBox msgBox;
+QMessageBox msgBox(this);
 msgBox.setText("The document has been modified.");
 msgBox.exec();
 //! [5]
 
 //! [6]
-QMessageBox msgBox;
+QMessageBox msgBox(this);
 msgBox.setText("The document has been modified.");
 msgBox.setInformativeText("Do you want to save your changes?");
 msgBox.setStandardButtons(QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel);
diff --git a/src/widgets/styles/qstylesheetstyle.cpp b/src/widgets/styles/qstylesheetstyle.cpp
index 08178e7b685..f4b21d3b70d 100644
--- a/src/widgets/styles/qstylesheetstyle.cpp
+++ b/src/widgets/styles/qstylesheetstyle.cpp
@@ -5269,7 +5269,11 @@ QSize QStyleSheetStyle::sizeFromContents(ContentsType ct, const QStyleOption *op
         if (const QStyleOptionSpinBox *spinbox = qstyleoption_cast<const QStyleOptionSpinBox *>(opt)) {
             if (rule.baseStyleCanDraw()) {
                 sz = baseStyle()->sizeFromContents(ct, opt, sz, w);
-            } else if (spinbox->buttonSymbols != QAbstractSpinBox::NoButtons) {
+                if (rule.hasBox() || !rule.hasNativeBorder())
+                    sz = rule.boxSize(sz);
+                return sz;
+            }
+            if (spinbox->buttonSymbols != QAbstractSpinBox::NoButtons) {
                 // Add some space for the up/down buttons
                 QRenderRule subRule = renderRule(w, opt, PseudoElement_SpinBoxUpButton);
                 if (subRule.hasDrawable()) {