Don't add the watch folder before the user closes the Preferences window.

src/base/scanfoldersmodel.cpp

@@ -203,7 +203,7 @@ bool ScanFoldersModel::setData(const QModelIndex &index, const QVariant &value,
     return true;
 }
 
-ScanFoldersModel::PathStatus ScanFoldersModel::addPath(const QString &watchPath, const PathType &downloadType, const QString &downloadPath)
+ScanFoldersModel::PathStatus ScanFoldersModel::addPath(const QString &watchPath, const PathType &downloadType, const QString &downloadPath, bool addToFSWatcher)
 {
     QDir watchDir(watchPath);
     if (!watchDir.exists()) return DoesNotExist;
@@ -225,10 +225,23 @@ ScanFoldersModel::PathStatus ScanFoldersModel::addPath(const QString &watchPath,
     endInsertRows();
 
     // Start scanning
-    m_fsWatcher->addPath(canonicalWatchPath);
+    if (addToFSWatcher)
+        m_fsWatcher->addPath(canonicalWatchPath);
     return Ok;
 }
 
+void ScanFoldersModel::addToFSWatcher(const QStringList &watchPaths)
+{
+    if (!m_fsWatcher)
+        return; // addPath() wasn't called before this
+
+    foreach (const QString &path, watchPaths) {
+        QDir watchDir(path);
+        const QString &canonicalWatchPath = watchDir.canonicalPath();
+        m_fsWatcher->addPath(canonicalWatchPath);
+    }
+}
+
 void ScanFoldersModel::removePath(int row)
 {
     Q_ASSERT((row >= 0) && (row < rowCount()));

src/base/scanfoldersmodel.h

@@ -81,7 +81,9 @@ public:
 
     // TODO: removePaths(); singular version becomes private helper functions;
     // also: remove functions should take modelindexes
-    PathStatus addPath(const QString &watchPath, const PathType& downloadType, const QString &downloadPath);
+    PathStatus addPath(const QString &watchPath, const PathType& downloadType, const QString &downloadPath, bool addToFSWatcher = true);
+    // PRECONDITION: The paths must have been added with addPath() first.
+    void addToFSWatcher(const QStringList &watchPaths);
     void removePath(int row);
     bool removePath(const QString &path);
 

src/gui/options_imp.cpp

@@ -418,6 +418,7 @@ void options_imp::saveOptions()
     pref->useAdditionDialog(useAdditionDialog());
     pref->additionDialogFront(checkAdditionDialogFront->isChecked());
     pref->addTorrentsInPause(addTorrentsInPause());
+    ScanFoldersModel::instance()->addToFSWatcher(addedScanDirs);
     ScanFoldersModel::instance()->makePersistent();
     addedScanDirs.clear();
     pref->setTorrentExportDir(getTorrentExportDir());
@@ -1203,7 +1204,7 @@ void options_imp::on_addScanFolderButton_clicked()
     const QString dir = QFileDialog::getExistingDirectory(this, tr("Add directory to scan"),
                                                           Utils::Fs::toNativePath(Utils::Fs::folderName(pref->getScanDirsLastPath())));
     if (!dir.isEmpty()) {
-        const ScanFoldersModel::PathStatus status = ScanFoldersModel::instance()->addPath(dir, ScanFoldersModel::DOWNLOAD_IN_WATCH_FOLDER, QString());
+        const ScanFoldersModel::PathStatus status = ScanFoldersModel::instance()->addPath(dir, ScanFoldersModel::DOWNLOAD_IN_WATCH_FOLDER, QString(), false);
         QString error;
         switch (status) {
         case ScanFoldersModel::AlreadyInList: