diff --git a/src/kcms/kio/cache.h b/src/kcms/kio/cache.h
--- a/src/kcms/kio/cache.h
+++ b/src/kcms/kio/cache.h
@@ -43,7 +43,7 @@
 
 private Q_SLOTS:
   void configChanged();
-  void on_clearCacheButton_clicked();
+  void clearCache();
 
 private:
   Ui::CacheConfigUI ui;
diff --git a/src/kcms/kio/cache.cpp b/src/kcms/kio/cache.cpp
--- a/src/kcms/kio/cache.cpp
+++ b/src/kcms/kio/cache.cpp
@@ -43,6 +43,8 @@
                   :KCModule(parent)
 {
   ui.setupUi(this);
+
+  connect(ui.clearCacheButton, &QAbstractButton::clicked, this, &CacheConfigModule::clearCache);
 }
 
 CacheConfigModule::~CacheConfigModule()
@@ -118,7 +120,7 @@
   emit changed( true );
 }
 
-void CacheConfigModule::on_clearCacheButton_clicked()
+void CacheConfigModule::clearCache()
 {
     const QString exe = QFile::decodeName(CMAKE_INSTALL_FULL_LIBEXECDIR_KF5 "/kio_http_cache_cleaner");
 
diff --git a/src/kcms/kio/kcookiesmanagement.h b/src/kcms/kio/kcookiesmanagement.h
--- a/src/kcms/kio/kcookiesmanagement.h
+++ b/src/kcms/kio/kcookiesmanagement.h
@@ -68,12 +68,12 @@
     QString quickHelp() const override;
 
 private Q_SLOTS:
-    void on_deleteButton_clicked();
-    void on_deleteAllButton_clicked();
-    void on_reloadButton_clicked();
-    void on_cookiesTreeWidget_itemExpanded(QTreeWidgetItem*);
-    void on_cookiesTreeWidget_currentItemChanged(QTreeWidgetItem*);
-    void on_configPolicyButton_clicked();
+    void deleteCurrent();
+    void deleteAll();
+    void reload();
+    void listCookiesForDomain(QTreeWidgetItem*);
+    void updateForItem(QTreeWidgetItem*);
+    void configPolicy();
 
 private:
     void reset (bool deleteAll = false);
diff --git a/src/kcms/kio/kcookiesmanagement.cpp b/src/kcms/kio/kcookiesmanagement.cpp
--- a/src/kcms/kio/kcookiesmanagement.cpp
+++ b/src/kcms/kio/kcookiesmanagement.cpp
@@ -114,7 +114,14 @@
   mUi.setupUi(this);
   mUi.searchLineEdit->setTreeWidget(mUi.cookiesTreeWidget);
   mUi.cookiesTreeWidget->setColumnWidth(0, 150);
-  connect(mUi.cookiesTreeWidget, SIGNAL(itemDoubleClicked(QTreeWidgetItem*,int)), SLOT(on_configPolicyButton_clicked()));
+
+  connect(mUi.deleteButton, &QAbstractButton::clicked, this, &KCookiesManagement::deleteCurrent);
+  connect(mUi.deleteAllButton, &QAbstractButton::clicked, this, &KCookiesManagement::deleteAll);
+  connect(mUi.reloadButton, &QAbstractButton::clicked, this, &KCookiesManagement::reload);
+  connect(mUi.cookiesTreeWidget, &QTreeWidget::itemExpanded, this, &KCookiesManagement::listCookiesForDomain);
+  connect(mUi.cookiesTreeWidget, &QTreeWidget::currentItemChanged, this, &KCookiesManagement::updateForItem);
+  connect(mUi.cookiesTreeWidget, &QTreeWidget::itemDoubleClicked, this, &KCookiesManagement::configPolicy);
+  connect(mUi.configPolicyButton, &QAbstractButton::clicked, this, &KCookiesManagement::configPolicy);
 }
 
 KCookiesManagement::~KCookiesManagement()
@@ -193,7 +200,7 @@
 void KCookiesManagement::defaults()
 {
   reset();
-  on_reloadButton_clicked();
+  reload();
 }
 
 void KCookiesManagement::reset(bool deleteAll)
@@ -226,7 +233,7 @@
   return i18n("<h1>Cookie Management Quick Help</h1>" );
 }
 
-void KCookiesManagement::on_reloadButton_clicked()
+void KCookiesManagement::reload()
 {
   QDBusInterface kded(QStringLiteral("org.kde.kcookiejar5"), QStringLiteral("/modules/kcookiejar"), QStringLiteral("org.kde.KCookieServer"), QDBusConnection::sessionBus());
   QDBusReply<QStringList> reply = kded.call( QStringLiteral("findDomains") );
@@ -262,7 +269,7 @@
 
 Q_DECLARE_METATYPE( QList<int> )
 
-void KCookiesManagement::on_cookiesTreeWidget_itemExpanded(QTreeWidgetItem *item)
+void KCookiesManagement::listCookiesForDomain(QTreeWidgetItem *item)
 {
   CookieListViewItem* cookieDom = static_cast<CookieListViewItem*>(item);
   if (!cookieDom || cookieDom->cookiesLoaded())
@@ -338,7 +345,7 @@
   return true;
 }
 
-void KCookiesManagement::on_cookiesTreeWidget_currentItemChanged(QTreeWidgetItem* item)
+void KCookiesManagement::updateForItem(QTreeWidgetItem* item)
 {
   if (item) {
     CookieListViewItem* cookieItem = static_cast<CookieListViewItem*>(item);
@@ -365,7 +372,7 @@
   mUi.deleteButton->setEnabled(item != nullptr);
 }
 
-void KCookiesManagement::on_configPolicyButton_clicked()
+void KCookiesManagement::configPolicy()
 {
   // Get current item
   CookieListViewItem *item = static_cast<CookieListViewItem*>(mUi.cookiesTreeWidget->currentItem());
@@ -386,7 +393,7 @@
   }
 }
 
-void KCookiesManagement::on_deleteButton_clicked()
+void KCookiesManagement::deleteCurrent()
 {
   QTreeWidgetItem* currentItem = mUi.cookiesTreeWidget->currentItem();
   Q_ASSERT(currentItem); // the button is disabled otherwise
@@ -419,7 +426,7 @@
   emit changed( true );
 }
 
-void KCookiesManagement::on_deleteAllButton_clicked()
+void KCookiesManagement::deleteAll()
 {
   mDeleteAllFlag = true;
   reset(true);
diff --git a/src/kcms/kio/kproxydlg.h b/src/kcms/kio/kproxydlg.h
--- a/src/kcms/kio/kproxydlg.h
+++ b/src/kcms/kio/kproxydlg.h
@@ -48,14 +48,11 @@
     QString quickHelp() const override;
 
 private Q_SLOTS:
-    void on_autoDetectButton_clicked();
-    void on_showEnvValueCheckBox_toggled(bool);
-    void on_useSameProxyCheckBox_clicked(bool);
-
-    void on_manualProxyHttpEdit_textChanged(const QString&);
-    void on_manualNoProxyEdit_textChanged(const QString&);    
-    void on_manualProxyHttpEdit_textEdited(const QString&);
-    void on_manualProxyHttpSpinBox_valueChanged(int);
+    void autoDetect();
+    void showEnvValue(bool);
+    void setUseSameProxy(bool);
+    void syncProxies(const QString&);
+    void syncProxyPorts(int);
 
     void slotChanged();
 
diff --git a/src/kcms/kio/kproxydlg.cpp b/src/kcms/kio/kproxydlg.cpp
--- a/src/kcms/kio/kproxydlg.cpp
+++ b/src/kcms/kio/kproxydlg.cpp
@@ -226,6 +226,18 @@
     Q_UNUSED(args);
     mUi.setupUi(this);
 
+    connect(mUi.autoDetectButton, &QAbstractButton::clicked, this, &KProxyDialog::autoDetect);
+    connect(mUi.showEnvValueCheckBox, &QAbstractButton::toggled, this, &KProxyDialog::showEnvValue);
+    connect(mUi.useSameProxyCheckBox, &QAbstractButton::clicked, this, &KProxyDialog::setUseSameProxy);
+    connect(mUi.manualProxyHttpEdit, &QLineEdit::textChanged, this, [this](const QString &text) {
+        mUi.useSameProxyCheckBox->setEnabled(!text.isEmpty());
+    });
+    connect(mUi.manualNoProxyEdit, &QLineEdit::textChanged, this, [this](const QString &text) {
+        mUi.useReverseProxyCheckBox->setEnabled(!text.isEmpty());
+    });
+    connect(mUi.manualProxyHttpEdit, &QLineEdit::textEdited, this, &KProxyDialog::syncProxies);
+    connect(mUi.manualProxyHttpSpinBox, QOverload<int>::of(&QSpinBox::valueChanged), this, &KProxyDialog::syncProxyPorts);
+
     mUi.systemProxyGroupBox->setVisible(false);
     mUi.manualProxyGroupBox->setVisible(false);
     mUi.autoDetectButton->setVisible(false);
@@ -452,7 +464,7 @@
     return false;
 }
 
-void KProxyDialog::on_autoDetectButton_clicked()
+void KProxyDialog::autoDetect()
 {
     const bool showValue = mUi.showEnvValueCheckBox->isChecked();
     bool wasChanged = false;
@@ -467,17 +479,7 @@
         emit changed (true);
 }
 
-void KProxyDialog::on_manualProxyHttpEdit_textChanged(const QString& text)
-{
-    mUi.useSameProxyCheckBox->setEnabled(!text.isEmpty());
-}
-
-void KProxyDialog::on_manualNoProxyEdit_textChanged (const QString& text)
-{
-    mUi.useReverseProxyCheckBox->setEnabled(!text.isEmpty());
-}
-
-void KProxyDialog::on_manualProxyHttpEdit_textEdited(const QString& text)
+void KProxyDialog::syncProxies(const QString& text)
 {
     if (!mUi.useSameProxyCheckBox->isChecked()) {
         return;
@@ -488,7 +490,7 @@
     mUi.manualProxySocksEdit->setText(text);
 }
 
-void KProxyDialog::on_manualProxyHttpSpinBox_valueChanged (int value)
+void KProxyDialog::syncProxyPorts(int value)
 {
     if (!mUi.useSameProxyCheckBox->isChecked()) {
         return;
@@ -499,7 +501,7 @@
     mUi.manualProxySocksSpinBox->setValue(value);
 }
 
-void KProxyDialog::on_showEnvValueCheckBox_toggled (bool on)
+void KProxyDialog::showEnvValue(bool on)
 {
     if (on) {
         showSystemProxyUrl(mUi.systemProxyHttpEdit, &mProxyMap[mUi.systemProxyHttpEdit->objectName()]);
@@ -522,7 +524,7 @@
     mUi.systemNoProxyEdit->setEnabled(true);
 }
 
-void KProxyDialog::on_useSameProxyCheckBox_clicked(bool on)
+void KProxyDialog::setUseSameProxy(bool on)
 {
     if (on) {
         mProxyMap[QStringLiteral("ManProxyHttps")] = manualProxyToText (mUi.manualProxyHttpsEdit, mUi.manualProxyHttpsSpinBox, QL1C (' '));
diff --git a/src/kcms/kio/useragentdlg.h b/src/kcms/kio/useragentdlg.h
--- a/src/kcms/kio/useragentdlg.h
+++ b/src/kcms/kio/useragentdlg.h
@@ -48,18 +48,10 @@
 private Q_SLOTS:
   void updateButtons();
 
-  void on_newButton_clicked();
-  void on_changeButton_clicked();
-  void on_deleteButton_clicked();
-  void on_deleteAllButton_clicked();
-
-  void on_sendUACheckBox_clicked();
-  void on_osNameCheckBox_clicked();
-  void on_osVersionCheckBox_clicked();
-  void on_processorTypeCheckBox_clicked();
-  void on_languageCheckBox_clicked();
-  void on_sitePolicyTreeWidget_itemSelectionChanged();
-  void on_sitePolicyTreeWidget_itemDoubleClicked(QTreeWidgetItem*, int);
+  void newSitePolicy();
+  void changeSitePolicy(QTreeWidgetItem*);
+  void deleteSitePolicies();
+  void deleteAllSitePolicies();
 
 private:
   void changeDefaultUAModifiers();
diff --git a/src/kcms/kio/useragentdlg.cpp b/src/kcms/kio/useragentdlg.cpp
--- a/src/kcms/kio/useragentdlg.cpp
+++ b/src/kcms/kio/useragentdlg.cpp
@@ -62,20 +62,30 @@
     ui.changeButton->setIcon (QIcon::fromTheme(QStringLiteral("edit-rename")));
     ui.deleteButton->setIcon (QIcon::fromTheme(QStringLiteral("list-remove")));
     ui.deleteAllButton->setIcon (QIcon::fromTheme(QStringLiteral("edit-delete")));
+
+    connect(ui.newButton, &QAbstractButton::clicked, this, &UserAgentDlg::newSitePolicy);
+    connect(ui.changeButton, &QAbstractButton::clicked,
+            this, [this]() { changeSitePolicy(ui.sitePolicyTreeWidget->currentItem()); });
+    connect(ui.deleteButton, &QAbstractButton::clicked, this, &UserAgentDlg::deleteSitePolicies);
+    connect(ui.deleteAllButton, &QAbstractButton::clicked, this, &UserAgentDlg::deleteAllSitePolicies);
+
+    connect(ui.sendUACheckBox, &QAbstractButton::clicked, this, [this]() { configChanged(); });
+    connect(ui.osNameCheckBox, &QAbstractButton::clicked, this, [this]() { changeDefaultUAModifiers(); });
+    connect(ui.osVersionCheckBox, &QAbstractButton::clicked, this, [this]() { changeDefaultUAModifiers(); });
+    connect(ui.processorTypeCheckBox, &QAbstractButton::clicked, this, [this]() { changeDefaultUAModifiers(); });
+    connect(ui.languageCheckBox, &QAbstractButton::clicked, this, [this]() { changeDefaultUAModifiers(); });
+
+    connect(ui.sitePolicyTreeWidget, &QTreeWidget::itemSelectionChanged, this, &UserAgentDlg::updateButtons);
+    connect(ui.sitePolicyTreeWidget, &QTreeWidget::itemDoubleClicked, this, &UserAgentDlg::changeSitePolicy);
 }
 
 UserAgentDlg::~UserAgentDlg()
 {
     delete m_userAgentInfo;
     delete m_config;
 }
 
-void UserAgentDlg::on_sendUACheckBox_clicked()
-{
-    configChanged();
-}
-
-void UserAgentDlg::on_newButton_clicked()
+void UserAgentDlg::newSitePolicy()
 {
     const QPointer<UserAgentSelectorDlg> pdlg (new UserAgentSelectorDlg (m_userAgentInfo, this));
     pdlg->setWindowTitle(i18nc ("@title:window", "Add Identification"));
@@ -93,12 +103,7 @@
     delete pdlg;
 }
 
-void UserAgentDlg::on_changeButton_clicked()
-{
-    on_sitePolicyTreeWidget_itemDoubleClicked (ui.sitePolicyTreeWidget->currentItem(), -1);
-}
-
-void UserAgentDlg::on_deleteButton_clicked()
+void UserAgentDlg::deleteSitePolicies()
 {
     SiteList selectedItems = ui.sitePolicyTreeWidget->selectedItems();
     SiteListIterator endIt = selectedItems.end();
@@ -110,34 +115,14 @@
     configChanged();
 }
 
-void UserAgentDlg::on_deleteAllButton_clicked()
+void UserAgentDlg::deleteAllSitePolicies()
 {
     ui.sitePolicyTreeWidget->clear();
     updateButtons();
     configChanged();
 }
 
-void UserAgentDlg::on_osNameCheckBox_clicked()
-{
-    changeDefaultUAModifiers();
-}
-
-void UserAgentDlg::on_osVersionCheckBox_clicked()
-{
-    changeDefaultUAModifiers();
-}
-
-void UserAgentDlg::on_processorTypeCheckBox_clicked()
-{
-    changeDefaultUAModifiers();
-}
-
-void UserAgentDlg::on_languageCheckBox_clicked()
-{
-    changeDefaultUAModifiers();
-}
-
-void UserAgentDlg::on_sitePolicyTreeWidget_itemDoubleClicked (QTreeWidgetItem* item, int)
+void UserAgentDlg::changeSitePolicy(QTreeWidgetItem* item)
 {
     if (item) {
         // Store the current site name...
@@ -227,11 +212,6 @@
     ui.deleteAllButton->setEnabled (hasItems);
 }
 
-void UserAgentDlg::on_sitePolicyTreeWidget_itemSelectionChanged()
-{
-    updateButtons();
-}
-
 void UserAgentDlg::load()
 {
     ui.sitePolicyTreeWidget->clear();