QCombobox: propagate the palette to the embedded line edit

Let the new created embedded QLineEdit use the palette from QCombobox,
when calling [setEditable(true)]

Fixes: QTBUG-81533
Pick-to: 5.15
Change-Id: Ia406dd8122a348e185f0e94d027646b95eeaa76e
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
index 30f51e1d42..e22a900676 100644
--- a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
+++ b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
@@ -166,6 +166,7 @@ private slots:
     void inputMethodUpdate();
     void task_QTBUG_52027_mapCompleterIndex();
     void checkMenuItemPosWhenStyleSheetIsSet();
+    void checkEmbeddedLineEditWhenStyleSheetIsSet();
 
 private:
     PlatformInputContext m_platformInputContext;
@@ -3515,5 +3516,31 @@ void tst_QComboBox::checkMenuItemPosWhenStyleSheetIsSet()
     qApp->setStyleSheet(oldCss);
 }
 
+void tst_QComboBox::checkEmbeddedLineEditWhenStyleSheetIsSet()
+{
+    QString newCss = "QWidget { background-color: red; color: white; }";
+    QString oldCss = qApp->styleSheet();
+    qApp->setStyleSheet(newCss);
+
+    QWidget topLevel;
+    auto layout = new QVBoxLayout(&topLevel);
+    topLevel.setLayout(layout);
+    auto comboBox = new QComboBox;
+    layout->addWidget(comboBox);
+    topLevel.show();
+    comboBox->setEditable(true);
+    QApplication::setActiveWindow(&topLevel);
+    QVERIFY(QTest::qWaitForWindowActive(&topLevel));
+
+    QImage grab = comboBox->grab().toImage();
+    auto color = grab.pixelColor(grab.rect().center());
+
+    QVERIFY(color.red() > 240);
+    QVERIFY(color.green() < 20);
+    QVERIFY(color.blue() < 20);
+
+    qApp->setStyleSheet(oldCss);
+}
+
 QTEST_MAIN(tst_QComboBox)
 #include "tst_qcombobox.moc"