3 files changed, 62 insertions, 9 deletions

diff --git a/src/widgets/widgets/qcombobox.cpp b/src/widgets/widgets/qcombobox.cpp
index c4596d9e78..4e2f9c23a0 100644
--- a/src/widgets/widgets/qcombobox.cpp
+++ b/src/widgets/widgets/qcombobox.cpp
@@ -531,8 +531,6 @@ QComboBoxPrivateContainer::QComboBoxPrivateContainer(QAbstractItemView *itemView
         setLineWidth(1);
     }
 
-    setFrameStyle(combo->style()->styleHint(QStyle::SH_ComboBox_PopupFrameStyle, &opt, combo));
-
     if (top) {
         layout->insertWidget(0, top);
         connect(top, SIGNAL(doScroll(int)), this, SLOT(scrollItemView(int)));
@@ -545,7 +543,7 @@ QComboBoxPrivateContainer::QComboBoxPrivateContainer(QAbstractItemView *itemView
     // Some styles (Mac) have a margin at the top and bottom of the popup.
     layout->insertSpacing(0, 0);
     layout->addSpacing(0);
-    updateTopBottomMargin();
+    updateStyleSettings();
 }
 
 void QComboBoxPrivateContainer::scrollItemView(int action)
@@ -728,14 +726,20 @@ void QComboBoxPrivateContainer::updateTopBottomMargin()
     boxLayout->invalidate();
 }
 
+void QComboBoxPrivateContainer::updateStyleSettings()
+{
+    // add scroller arrows if style needs them
+    QStyleOptionComboBox opt = comboStyleOption();
+    view->setMouseTracking(combo->style()->styleHint(QStyle::SH_ComboBox_ListMouseTracking, &opt, combo) ||
+                           combo->style()->styleHint(QStyle::SH_ComboBox_Popup, &opt, combo));
+    setFrameStyle(combo->style()->styleHint(QStyle::SH_ComboBox_PopupFrameStyle, &opt, combo));
+    updateTopBottomMargin();
+}
+
 void QComboBoxPrivateContainer::changeEvent(QEvent *e)
 {
-    if (e->type() == QEvent::StyleChange) {
-        QStyleOptionComboBox opt = comboStyleOption();
-        view->setMouseTracking(combo->style()->styleHint(QStyle::SH_ComboBox_ListMouseTracking, &opt, combo) ||
-                               combo->style()->styleHint(QStyle::SH_ComboBox_Popup, &opt, combo));
-        setFrameStyle(combo->style()->styleHint(QStyle::SH_ComboBox_PopupFrameStyle, &opt, combo));
-    }
+    if (e->type() == QEvent::StyleChange)
+        updateStyleSettings();
 
     QFrame::changeEvent(e);
 }
@@ -2966,6 +2970,8 @@ void QComboBox::changeEvent(QEvent *e)
     Q_D(QComboBox);
     switch (e->type()) {
     case QEvent::StyleChange:
+        if (d->container)
+            d->container->updateStyleSettings();
         d->updateDelegate();
 #ifdef Q_OS_MAC
     case QEvent::MacSizeChange:
diff --git a/src/widgets/widgets/qcombobox_p.h b/src/widgets/widgets/qcombobox_p.h
index 16ded8f1a4..df3421692f 100644
--- a/src/widgets/widgets/qcombobox_p.h
+++ b/src/widgets/widgets/qcombobox_p.h
@@ -222,6 +222,7 @@ public:
     int topMargin() const;
     int bottomMargin() const { return topMargin(); }
     void updateTopBottomMargin();
+    void updateStyleSettings();
 
     QTimer blockMouseReleaseTimer;
     QBasicTimer adjustSizeTimer;
diff --git a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
index 909b0b4aaa..162b90d16b 100644
--- a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
+++ b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
@@ -169,6 +169,7 @@ private slots:
     void task_QTBUG_52027_mapCompleterIndex();
     void checkMenuItemPosWhenStyleSheetIsSet();
     void checkEmbeddedLineEditWhenStyleSheetIsSet();
+    void propagateStyleChanges();
 
 private:
     PlatformInputContext m_platformInputContext;
@@ -3544,5 +3545,50 @@ void tst_QComboBox::checkEmbeddedLineEditWhenStyleSheetIsSet()
     qApp->setStyleSheet(oldCss);
 }
 
+/*!
+    Tests that the style-based frame style propagates to the internal container
+    widget of QComboBox when the style changes by verifying that the respective
+    styleHint is asked for when the style changes.
+
+    See QTBUG-92488
+*/
+void tst_QComboBox::propagateStyleChanges()
+{
+    class FrameStyle : public QProxyStyle
+    {
+    public:
+        FrameStyle(int frameStyle, QStyle *style = nullptr)
+            : QProxyStyle(style), frameStyle(frameStyle)
+        {}
+
+        int styleHint(QStyle::StyleHint hint, const QStyleOption *opt,
+                      const QWidget *widget, QStyleHintReturn *returnData) const
+        {
+            if (hint == QStyle::SH_ComboBox_PopupFrameStyle) {
+                inquired = true;
+                return frameStyle;
+            }
+            return QProxyStyle::styleHint(hint, opt, widget, returnData);
+        }
+
+        int frameStyle;
+        mutable bool inquired = false;
+    };
+
+    FrameStyle framelessStyle(QFrame::NoFrame);
+    FrameStyle frameStyle(QFrame::Plain | QFrame::Sunken);
+
+    QComboBox combo;
+    // container will be created and take settings from this style
+    combo.setStyle(&framelessStyle);
+    QVERIFY(framelessStyle.inquired);
+    combo.addItem(QLatin1String("Open"));
+    combo.addItem(QLatin1String("Close"));
+    // needed because of QComboBox's adjustSizeTimer not doing anything otherwise
+    combo.setSizeAdjustPolicy(QComboBox::AdjustToContents);
+    combo.setStyle(&frameStyle);
+    QVERIFY(frameStyle.inquired);
+}
+
 QTEST_MAIN(tst_QComboBox)
 #include "tst_qcombobox.moc"