diff --git a/src/base/bittorrent/torrenthandle.cpp b/src/base/bittorrent/torrenthandle.cpp
index 5ad0565ab..005084b30 100644
--- a/src/base/bittorrent/torrenthandle.cpp
+++ b/src/base/bittorrent/torrenthandle.cpp
@@ -2187,7 +2187,7 @@ void TorrentHandle::setSuperSeeding(const bool enable)
 #endif
 }
 
-void TorrentHandle::flushCache()
+void TorrentHandle::flushCache() const
 {
     m_nativeHandle.flush_cache();
 }
diff --git a/src/base/bittorrent/torrenthandle.h b/src/base/bittorrent/torrenthandle.h
index 4a52a9b89..80ce1af9a 100644
--- a/src/base/bittorrent/torrenthandle.h
+++ b/src/base/bittorrent/torrenthandle.h
@@ -324,7 +324,7 @@ namespace BitTorrent
         void setUploadLimit(int limit);
         void setDownloadLimit(int limit);
         void setSuperSeeding(bool enable);
-        void flushCache();
+        void flushCache() const;
         void addTrackers(const QVector<TrackerEntry> &trackers);
         void replaceTrackers(const QVector<TrackerEntry> &trackers);
         void addUrlSeeds(const QVector<QUrl> &urlSeeds);
diff --git a/src/gui/previewselectdialog.cpp b/src/gui/previewselectdialog.cpp
index 821912a72..fc3cc0d20 100644
--- a/src/gui/previewselectdialog.cpp
+++ b/src/gui/previewselectdialog.cpp
@@ -45,7 +45,7 @@
 
 #define SETTINGS_KEY(name) "PreviewSelectDialog/" name
 
-PreviewSelectDialog::PreviewSelectDialog(QWidget *parent, BitTorrent::TorrentHandle *const torrent)
+PreviewSelectDialog::PreviewSelectDialog(QWidget *parent, const BitTorrent::TorrentHandle *torrent)
     : QDialog(parent)
     , m_ui(new Ui::PreviewSelectDialog)
     , m_torrent(torrent)
@@ -53,13 +53,12 @@ PreviewSelectDialog::PreviewSelectDialog(QWidget *parent, BitTorrent::TorrentHan
     , m_storeTreeHeaderState(SETTINGS_KEY("HeaderState"))
 {
     m_ui->setupUi(this);
-    setAttribute(Qt::WA_DeleteOnClose);
 
     m_ui->buttonBox->button(QDialogButtonBox::Ok)->setText(tr("Preview"));
     connect(m_ui->buttonBox, &QDialogButtonBox::accepted, this, &PreviewSelectDialog::previewButtonClicked);
     connect(m_ui->buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
 
-    Preferences *const pref = Preferences::instance();
+    const Preferences *pref = Preferences::instance();
     // Preview list
     m_previewListModel = new QStandardItemModel(0, NB_COLUMNS, this);
     m_previewListModel->setHeaderData(NAME, Qt::Horizontal, tr("Name"));
diff --git a/src/gui/previewselectdialog.h b/src/gui/previewselectdialog.h
index a9dc54749..8ab018121 100644
--- a/src/gui/previewselectdialog.h
+++ b/src/gui/previewselectdialog.h
@@ -60,26 +60,25 @@ public:
         NB_COLUMNS
     };
 
-    PreviewSelectDialog(QWidget *parent, BitTorrent::TorrentHandle *const torrent);
+    PreviewSelectDialog(QWidget *parent, const BitTorrent::TorrentHandle *torrent);
     ~PreviewSelectDialog();
 
 signals:
     void readyToPreviewFile(QString) const;
 
-protected:
-    void showEvent(QShowEvent *event) override;
-
 private slots:
     void previewButtonClicked();
 
 private:
+    void showEvent(QShowEvent *event) override;
+
     void loadWindowState();
     void saveWindowState();
 
     Ui::PreviewSelectDialog *m_ui;
     QStandardItemModel *m_previewListModel;
     PreviewListDelegate *m_listDelegate;
-    BitTorrent::TorrentHandle *const m_torrent;
+    const BitTorrent::TorrentHandle *m_torrent;
     bool m_headerStateInitialized = false;
 
     // Settings
diff --git a/src/gui/transferlistwidget.cpp b/src/gui/transferlistwidget.cpp
index acf2c193a..0887af09b 100644
--- a/src/gui/transferlistwidget.cpp
+++ b/src/gui/transferlistwidget.cpp
@@ -501,9 +501,10 @@ void TransferListWidget::openSelectedTorrentsFolder() const
 
 void TransferListWidget::previewSelectedTorrents()
 {
-    for (BitTorrent::TorrentHandle *const torrent : asConst(getSelectedTorrents())) {
+    for (const BitTorrent::TorrentHandle *torrent : asConst(getSelectedTorrents())) {
         if (torrentContainsPreviewableFiles(torrent)) {
-            const auto *dialog = new PreviewSelectDialog(this, torrent);
+            auto *dialog = new PreviewSelectDialog(this, torrent);
+            dialog->setAttribute(Qt::WA_DeleteOnClose);
             connect(dialog, &PreviewSelectDialog::readyToPreviewFile, this, &TransferListWidget::previewFile);
         }
         else {