Exporter: make it modeless

src/widgets/dialogs/exportdialog.cpp

@@ -53,6 +53,8 @@ ExportDialog::ExportDialog(Notebook *p_notebook,
 
     restoreFields(m_option);
 
+    setWindowFlags(windowFlags() | Qt::WindowMinimizeButtonHint);
+
     connect(this, &QDialog::finished,
             this, [this]() {
                 saveFields(m_option);

src/widgets/mainwindow.cpp

@@ -857,12 +857,17 @@ void MainWindow::exportNotes()
     if (noteNode && !noteNode->hasContent()) {
         noteNode = nullptr;
     }
-    ExportDialog dialog(currentNotebook,
+    auto dialog = new ExportDialog(currentNotebook,
                                    folderNode,
                                    noteNode,
                                    viewWindow ? viewWindow->getBuffer() : nullptr,
-                        this);
-    dialog.exec();
+                                   nullptr);
+    connect(dialog, &QDialog::finished,
+            this, [this, dialog]() {
+                dialog->deleteLater();
+            });
+    // Let it be able to run at background.
+    dialog->show();
 }
 
 void MainWindow::showTips(const QString &p_message, int p_timeoutMilliseconds)