titler: Remember to show background

src/kdenlivesettings.kcfg

@@ -1033,5 +1033,9 @@
         <label>Default background for titler.</label>
         <default>0</default>
         </entry>
+        <entry name="titlerShowbg" type="Bool">
+        <label>Show titler background.</label>
+        <default>false</default>
+        </entry>
    </group>
 </kcfg>

src/titler/titlewidget.cpp

@@ -225,7 +225,12 @@ TitleWidget::TitleWidget(const QUrl &url, const Timecode &tc, QString projectTit
     connect(buttonAlignCenter, &QAbstractButton::clicked, this, &TitleWidget::slotUpdateText);
     connect(edit_gradient, &QAbstractButton::clicked, this, &TitleWidget::slotEditGradient);
     connect(edit_rect_gradient, &QAbstractButton::clicked, this, &TitleWidget::slotEditGradient);
-    connect(displayBg, &QCheckBox::stateChanged, this, &TitleWidget::displayBackgroundFrame);
+
+    displayBg->setChecked(KdenliveSettings::titlerShowbg());
+    connect(displayBg, static_cast<void (QCheckBox::*)(int)>(&QCheckBox::stateChanged), [&] (int state) {
+        KdenliveSettings::setTitlerShowbg(state == Qt::Checked);
+        displayBackgroundFrame();
+    });
 
     connect(m_unicodeDialog, &UnicodeDialog::charSelected, this, &TitleWidget::slotInsertUnicodeString);