diff --git a/src/app/stacktracedialog.h b/src/app/stacktracedialog.h
index cf40e73f0..ff9b0c81e 100644
--- a/src/app/stacktracedialog.h
+++ b/src/app/stacktracedialog.h
@@ -30,21 +30,27 @@
 #ifndef STACKTRACEDIALOG_H
 #define STACKTRACEDIALOG_H
 
-#include <QString>
 #include <QDialog>
+#include <QString>
 
 #include "base/utils/misc.h"
 #include "ui_stacktracedialog.h"
 
-class StacktraceDialog : public QDialog, private Ui::StacktraceDialog
+class StacktraceDialog : public QDialog
 {
     Q_OBJECT
 
 public:
     StacktraceDialog(QWidget *parent = nullptr)
         : QDialog(parent)
+        , m_ui(new Ui::StacktraceDialog)
     {
-        setupUi(this);
+        m_ui->setupUi(this);
+    }
+
+    ~StacktraceDialog()
+    {
+        delete m_ui;
     }
 
     void setStacktraceString(const QString &sigName, const QString &trace)
@@ -79,8 +85,11 @@ public:
                      , sigName
                      , trace);
 
-        errorText->setHtml(htmlStr);
+        m_ui->errorText->setHtml(htmlStr);
     }
+
+private:
+    Ui::StacktraceDialog *m_ui;
 };
 
 #endif // STACKTRACEDIALOG_H
diff --git a/src/gui/aboutdialog.h b/src/gui/aboutdialog.h
index 0881dfa0e..7ab927f2f 100644
--- a/src/gui/aboutdialog.h
+++ b/src/gui/aboutdialog.h
@@ -36,21 +36,22 @@
 #include "ui_aboutdialog.h"
 #include "utils.h"
 
-class AboutDialog : public QDialog, private Ui::AboutDialog
+class AboutDialog : public QDialog
 {
     Q_OBJECT
 
 public:
     AboutDialog(QWidget *parent)
         : QDialog(parent)
+        , m_ui(new Ui::AboutDialog)
     {
-        setupUi(this);
+        m_ui->setupUi(this);
         setAttribute(Qt::WA_DeleteOnClose);
 
         // Title
-        labelName->setText(QString("<b><h2>qBittorrent " QBT_VERSION " (%1-bit)</h2></b>").arg(QT_POINTER_SIZE * 8));
+        m_ui->labelName->setText(QString("<b><h2>qBittorrent " QBT_VERSION " (%1-bit)</h2></b>").arg(QT_POINTER_SIZE * 8));
 
-        logo->setPixmap(Utils::Gui::scaledPixmapSvg(":/icons/skin/qbittorrent-tray.svg", this, 32));
+        m_ui->logo->setPixmap(Utils::Gui::scaledPixmapSvg(":/icons/skin/qbittorrent-tray.svg", this, 32));
 
         // About
         QString aboutText = QString(
@@ -68,40 +69,48 @@ public:
                 , tr("Home Page:")
                 , tr("Forum:")
                 , tr("Bug Tracker:"));
-        labelAbout->setText(aboutText);
+        m_ui->labelAbout->setText(aboutText);
 
-        labelMascot->setPixmap(Utils::Gui::scaledPixmap(":/icons/skin/mascot.png", this));
+        m_ui->labelMascot->setPixmap(Utils::Gui::scaledPixmap(":/icons/skin/mascot.png", this));
 
         // Thanks
         QFile thanksfile(":/thanks.html");
         if (thanksfile.open(QIODevice::ReadOnly | QIODevice::Text)) {
-            textBrowserThanks->setHtml(QString::fromUtf8(thanksfile.readAll().constData()));
+            m_ui->textBrowserThanks->setHtml(QString::fromUtf8(thanksfile.readAll().constData()));
             thanksfile.close();
         }
 
         // Translation
         QFile translatorsfile(":/translators.html");
         if (translatorsfile.open(QIODevice::ReadOnly | QIODevice::Text)) {
-            textBrowserTranslation->setHtml(QString::fromUtf8(translatorsfile.readAll().constData()));
+            m_ui->textBrowserTranslation->setHtml(QString::fromUtf8(translatorsfile.readAll().constData()));
             translatorsfile.close();
         }
 
         // License
         QFile licensefile(":/gpl.html");
         if (licensefile.open(QIODevice::ReadOnly | QIODevice::Text)) {
-            textBrowserLicense->setHtml(QString::fromUtf8(licensefile.readAll().constData()));
+            m_ui->textBrowserLicense->setHtml(QString::fromUtf8(licensefile.readAll().constData()));
             licensefile.close();
         }
 
         // Libraries
-        labelQtVer->setText(QT_VERSION_STR);
-        labelLibtVer->setText(Utils::Misc::libtorrentVersionString());
-        labelBoostVer->setText(Utils::Misc::boostVersionString());
-        labelOpensslVer->setText(Utils::Misc::opensslVersionString());
+        m_ui->labelQtVer->setText(QT_VERSION_STR);
+        m_ui->labelLibtVer->setText(Utils::Misc::libtorrentVersionString());
+        m_ui->labelBoostVer->setText(Utils::Misc::boostVersionString());
+        m_ui->labelOpensslVer->setText(Utils::Misc::opensslVersionString());
 
         Utils::Gui::resize(this);
         show();
     }
+
+    ~AboutDialog()
+    {
+        delete m_ui;
+    }
+
+private:
+    Ui::AboutDialog *m_ui;
 };
 
 #endif // ABOUTDIALOG_H
diff --git a/src/gui/deletionconfirmationdialog.h b/src/gui/deletionconfirmationdialog.h
index 6e929c76b..949f06fb7 100644
--- a/src/gui/deletionconfirmationdialog.h
+++ b/src/gui/deletionconfirmationdialog.h
@@ -33,42 +33,46 @@
 #include <QPushButton>
 
 #include "base/preferences.h"
-#include "base/utils/misc.h"
-#include "base/utils/string.h"
 #include "guiiconprovider.h"
 #include "ui_deletionconfirmationdialog.h"
 #include "utils.h"
 
-class DeletionConfirmationDialog : public QDialog, private Ui::DeletionConfirmationDialog
+class DeletionConfirmationDialog : public QDialog
 {
     Q_OBJECT
 
 public:
     DeletionConfirmationDialog(QWidget *parent, const int &size, const QString &name, bool defaultDeleteFiles)
         : QDialog(parent)
+        , m_ui(new Ui::DeletionConfirmationDialog)
     {
-        setupUi(this);
+        m_ui->setupUi(this);
         if (size == 1)
-            label->setText(tr("Are you sure you want to delete '%1' from the transfer list?", "Are you sure you want to delete 'ubuntu-linux-iso' from the transfer list?").arg(name.toHtmlEscaped()));
+            m_ui->label->setText(tr("Are you sure you want to delete '%1' from the transfer list?", "Are you sure you want to delete 'ubuntu-linux-iso' from the transfer list?").arg(name.toHtmlEscaped()));
         else
-            label->setText(tr("Are you sure you want to delete these %1 torrents from the transfer list?", "Are you sure you want to delete these 5 torrents from the transfer list?").arg(QString::number(size)));
+            m_ui->label->setText(tr("Are you sure you want to delete these %1 torrents from the transfer list?", "Are you sure you want to delete these 5 torrents from the transfer list?").arg(QString::number(size)));
         // Icons
         const QSize iconSize = Utils::Gui::largeIconSize();
-        labelWarning->setPixmap(GuiIconProvider::instance()->getIcon("dialog-warning").pixmap(iconSize));
-        labelWarning->setFixedWidth(iconSize.width());
-        rememberBtn->setIcon(GuiIconProvider::instance()->getIcon("object-locked"));
-        rememberBtn->setIconSize(Utils::Gui::mediumIconSize());
+        m_ui->labelWarning->setPixmap(GuiIconProvider::instance()->getIcon("dialog-warning").pixmap(iconSize));
+        m_ui->labelWarning->setFixedWidth(iconSize.width());
+        m_ui->rememberBtn->setIcon(GuiIconProvider::instance()->getIcon("object-locked"));
+        m_ui->rememberBtn->setIconSize(Utils::Gui::mediumIconSize());
 
-        checkPermDelete->setChecked(defaultDeleteFiles || Preferences::instance()->deleteTorrentFilesAsDefault());
-        connect(checkPermDelete, &QCheckBox::clicked, this, &DeletionConfirmationDialog::updateRememberButtonState);
-        buttonBox->button(QDialogButtonBox::Cancel)->setFocus();
+        m_ui->checkPermDelete->setChecked(defaultDeleteFiles || Preferences::instance()->deleteTorrentFilesAsDefault());
+        connect(m_ui->checkPermDelete, &QCheckBox::clicked, this, &DeletionConfirmationDialog::updateRememberButtonState);
+        m_ui->buttonBox->button(QDialogButtonBox::Cancel)->setFocus();
 
         Utils::Gui::resize(this);
     }
 
+    ~DeletionConfirmationDialog()
+    {
+        delete m_ui;
+    }
+
     bool shouldDeleteLocalFiles() const
     {
-        return checkPermDelete->isChecked();
+        return m_ui->checkPermDelete->isChecked();
     }
 
     static bool askForDeletionConfirmation(QWidget *parent, bool &deleteLocalFiles, const int &size, const QString &name)
@@ -84,14 +88,17 @@ public:
 private slots:
     void updateRememberButtonState()
     {
-        rememberBtn->setEnabled(checkPermDelete->isChecked() != Preferences::instance()->deleteTorrentFilesAsDefault());
+        m_ui->rememberBtn->setEnabled(m_ui->checkPermDelete->isChecked() != Preferences::instance()->deleteTorrentFilesAsDefault());
     }
 
     void on_rememberBtn_clicked()
     {
-        Preferences::instance()->setDeleteTorrentFilesAsDefault(checkPermDelete->isChecked());
-        rememberBtn->setEnabled(false);
+        Preferences::instance()->setDeleteTorrentFilesAsDefault(m_ui->checkPermDelete->isChecked());
+        m_ui->rememberBtn->setEnabled(false);
     }
+
+private:
+    Ui::DeletionConfirmationDialog *m_ui;
 };
 
 #endif // DELETIONCONFIRMATIONDIALOG_H
diff --git a/src/gui/previewselectdialog.cpp b/src/gui/previewselectdialog.cpp
index 153c579c2..6120cc2bc 100644
--- a/src/gui/previewselectdialog.cpp
+++ b/src/gui/previewselectdialog.cpp
@@ -40,22 +40,24 @@
 #include "base/utils/fs.h"
 #include "base/utils/misc.h"
 #include "previewlistdelegate.h"
+#include "ui_previewselectdialog.h"
 #include "utils.h"
 
 #define SETTINGS_KEY(name) "PreviewSelectDialog/" name
 
 PreviewSelectDialog::PreviewSelectDialog(QWidget *parent, BitTorrent::TorrentHandle *const torrent)
     : QDialog(parent)
+    , m_ui(new Ui::PreviewSelectDialog)
     , m_torrent(torrent)
     , m_storeDialogSize(SETTINGS_KEY("Dimension"))
     , m_storeTreeHeaderState(SETTINGS_KEY("HeaderState"))
 {
-    setupUi(this);
+    m_ui->setupUi(this);
     setAttribute(Qt::WA_DeleteOnClose);
 
-    buttonBox->button(QDialogButtonBox::Ok)->setText(tr("Preview"));
-    connect(buttonBox, &QDialogButtonBox::accepted, this, &PreviewSelectDialog::previewButtonClicked);
-    connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
+    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();
     // Preview list
@@ -67,15 +69,15 @@ PreviewSelectDialog::PreviewSelectDialog(QWidget *parent, BitTorrent::TorrentHan
     // This hack fixes reordering of first column with Qt5.
     // https://github.com/qtproject/qtbase/commit/e0fc088c0c8bc61dbcaf5928b24986cd61a22777
     QTableView unused;
-    unused.setVerticalHeader(previewList->header());
-    previewList->header()->setParent(previewList);
+    unused.setVerticalHeader(m_ui->previewList->header());
+    m_ui->previewList->header()->setParent(m_ui->previewList);
     unused.setVerticalHeader(new QHeaderView(Qt::Horizontal));
 
-    previewList->setModel(m_previewListModel);
-    previewList->hideColumn(FILE_INDEX);
+    m_ui->previewList->setModel(m_previewListModel);
+    m_ui->previewList->hideColumn(FILE_INDEX);
     m_listDelegate = new PreviewListDelegate(this);
-    previewList->setItemDelegate(m_listDelegate);
-    previewList->setAlternatingRowColors(pref->useAlternatingRowColors());
+    m_ui->previewList->setItemDelegate(m_listDelegate);
+    m_ui->previewList->setAlternatingRowColors(pref->useAlternatingRowColors());
     // Fill list in
     QVector<qreal> fp = torrent->filesProgress();
     int nbFiles = torrent->filesCount();
@@ -96,8 +98,8 @@ PreviewSelectDialog::PreviewSelectDialog(QWidget *parent, BitTorrent::TorrentHan
 
     connect(this, SIGNAL(readyToPreviewFile(QString)), parent, SLOT(previewFile(QString)));
     m_previewListModel->sort(NAME);
-    previewList->header()->setSortIndicator(0, Qt::AscendingOrder);
-    previewList->selectionModel()->select(m_previewListModel->index(0, NAME), QItemSelectionModel::Select | QItemSelectionModel::Rows);
+    m_ui->previewList->header()->setSortIndicator(0, Qt::AscendingOrder);
+    m_ui->previewList->selectionModel()->select(m_previewListModel->index(0, NAME), QItemSelectionModel::Select | QItemSelectionModel::Rows);
 
     // Restore dialog state
     loadWindowState();
@@ -119,11 +121,12 @@ PreviewSelectDialog::~PreviewSelectDialog()
 
     delete m_previewListModel;
     delete m_listDelegate;
+    delete m_ui;
 }
 
 void PreviewSelectDialog::previewButtonClicked()
 {
-    QModelIndexList selectedIndexes = previewList->selectionModel()->selectedRows(FILE_INDEX);
+    QModelIndexList selectedIndexes = m_ui->previewList->selectionModel()->selectedRows(FILE_INDEX);
     if (selectedIndexes.isEmpty()) return;
 
     // Flush data
@@ -146,7 +149,7 @@ void PreviewSelectDialog::saveWindowState()
     // Persist dialog size
     m_storeDialogSize = size();
     // Persist TreeView Header state
-    m_storeTreeHeaderState = previewList->header()->saveState();
+    m_storeTreeHeaderState = m_ui->previewList->header()->saveState();
 }
 
 void PreviewSelectDialog::loadWindowState()
@@ -156,7 +159,7 @@ void PreviewSelectDialog::loadWindowState()
 
     // Restore TreeView Header state
     if (!m_storeTreeHeaderState.value().isEmpty()) {
-        m_headerStateInitialized = previewList->header()->restoreState(m_storeTreeHeaderState);
+        m_headerStateInitialized = m_ui->previewList->header()->restoreState(m_storeTreeHeaderState);
     }
 }
 
@@ -167,8 +170,8 @@ void PreviewSelectDialog::showEvent(QShowEvent *event)
     // Default size, have to be called after show(), because width is needed
     // Set Name column width to 60% of TreeView
     if (!m_headerStateInitialized) {
-        int nameSize = (previewList->size().width() * 0.6);
-        previewList->header()->resizeSection(0, nameSize);
+        int nameSize = (m_ui->previewList->size().width() * 0.6);
+        m_ui->previewList->header()->resizeSection(0, nameSize);
         m_headerStateInitialized = true;
     }
 }
diff --git a/src/gui/previewselectdialog.h b/src/gui/previewselectdialog.h
index 1b9e6bb47..a9dc54749 100644
--- a/src/gui/previewselectdialog.h
+++ b/src/gui/previewselectdialog.h
@@ -32,7 +32,6 @@
 #include <QDialog>
 
 #include "base/settingvalue.h"
-#include "ui_previewselectdialog.h"
 
 class QStandardItemModel;
 
@@ -40,9 +39,13 @@ namespace BitTorrent
 {
     class TorrentHandle;
 }
+namespace Ui
+{
+    class PreviewSelectDialog;
+}
 class PreviewListDelegate;
 
-class PreviewSelectDialog : public QDialog, private Ui::preview
+class PreviewSelectDialog : public QDialog
 {
     Q_OBJECT
 
@@ -73,6 +76,7 @@ private:
     void loadWindowState();
     void saveWindowState();
 
+    Ui::PreviewSelectDialog *m_ui;
     QStandardItemModel *m_previewListModel;
     PreviewListDelegate *m_listDelegate;
     BitTorrent::TorrentHandle *const m_torrent;
diff --git a/src/gui/previewselectdialog.ui b/src/gui/previewselectdialog.ui
index be7873d97..f37b0af45 100644
--- a/src/gui/previewselectdialog.ui
+++ b/src/gui/previewselectdialog.ui
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <ui version="4.0">
- <class>preview</class>
- <widget class="QDialog" name="preview">
+ <class>PreviewSelectDialog</class>
+ <widget class="QDialog" name="PreviewSelectDialog">
   <property name="geometry">
    <rect>
     <x>0</x>
diff --git a/src/gui/transferlistwidget.cpp b/src/gui/transferlistwidget.cpp
index aeef91e4a..218de9795 100644
--- a/src/gui/transferlistwidget.cpp
+++ b/src/gui/transferlistwidget.cpp
@@ -31,6 +31,7 @@
 #include <QClipboard>
 #include <QDebug>
 #include <QFileDialog>
+#include <QHeaderView>
 #include <QMenu>
 #include <QMessageBox>
 #include <QRegExp>
diff --git a/src/gui/transferlistwidget.h b/src/gui/transferlistwidget.h
index ff29b97a3..1c50a4d6c 100644
--- a/src/gui/transferlistwidget.h
+++ b/src/gui/transferlistwidget.h
@@ -38,8 +38,6 @@ namespace BitTorrent
 }
 
 class QShortcut;
-class QSortFilterProxyModel;
-class QStandardItemModel;
 
 class MainWindow;
 class TransferListDelegate;