[GUI] Handle ampersand in windowTitle

(cherry picked from commit eb0c980c1d)

src/Gui/Action.cpp

@@ -937,7 +937,9 @@ void RecentFilesAction::setFiles(const QStringList& files)
     for (int index = 0; index < numRecentFiles; index++) {
         QString numberLabel = numberToLabel(index + 1);
         QFileInfo fi(files[index]);
-        recentFiles[index]->setText(QStringLiteral("%1 %2").arg(numberLabel).arg(fi.fileName()));
+        QString fileName {fi.fileName()};
+        fileName.replace(QLatin1Char('&'), QStringLiteral("&&"));
+        recentFiles[index]->setText(QStringLiteral("%1 %2").arg(numberLabel, fileName));
         recentFiles[index]->setStatusTip(tr("Open file %1").arg(files[index]));
         recentFiles[index]->setToolTip(files[index]);  // set the full name that we need later for saving
         recentFiles[index]->setData(QVariant(index));

src/Gui/MDIView.cpp

@@ -527,4 +527,11 @@ QString MDIView::buildWindowTitle() const
     return windowTitle;
 }
 
+void MDIView::setWindowTitle(const QString& title)
+{
+    QString newerTitle {title};
+    newerTitle.replace(QLatin1Char('&'), QStringLiteral("&&"));
+    QMainWindow::setWindowTitle(newerTitle);
+}
+
 #include "moc_MDIView.cpp"

src/Gui/MDIView.h

@@ -78,6 +78,8 @@ public:
 
     /// build window title
     QString buildWindowTitle() const;
+    /// reimplementation of QWidget::setWindowTitle(const QString &title)
+    void setWindowTitle(const QString& title);
 
     /// Message handler
     bool onMsg(const char* pMsg, const char** ppReturn) override;