diff --git a/autotests/tabbox/mock_tabboxclient.h b/autotests/tabbox/mock_tabboxclient.h
index 9c82905622..aa6c37a9ed 100644
--- a/autotests/tabbox/mock_tabboxclient.h
+++ b/autotests/tabbox/mock_tabboxclient.h
@@ -41,10 +41,6 @@ public:
     {
         return true;
     }
-    bool isFirstInTabBox() const override
-    {
-        return false;
-    }
     int width() const override
     {
         return 100;
diff --git a/src/atoms.cpp b/src/atoms.cpp
index 040614269d..2439f1a913 100644
--- a/src/atoms.cpp
+++ b/src/atoms.cpp
@@ -48,7 +48,6 @@ Atoms::Atoms()
     , net_wm_sync_request_counter(QByteArrayLiteral("_NET_WM_SYNC_REQUEST_COUNTER"))
     , net_wm_sync_request(QByteArrayLiteral("_NET_WM_SYNC_REQUEST"))
     , kde_net_wm_shadow(QByteArrayLiteral("_KDE_NET_WM_SHADOW"))
-    , kde_first_in_window_list(QByteArrayLiteral("_KDE_FIRST_IN_WINDOWLIST"))
     , kde_color_sheme(QByteArrayLiteral("_KDE_NET_WM_COLOR_SCHEME"))
     , kde_skip_close_animation(QByteArrayLiteral("_KDE_NET_WM_SKIP_CLOSE_ANIMATION"))
     , kde_screen_edge_show(QByteArrayLiteral("_KDE_NET_WM_SCREEN_EDGE_SHOW"))
diff --git a/src/atoms.h b/src/atoms.h
index dbb4412c7c..2f7e7bc59e 100644
--- a/src/atoms.h
+++ b/src/atoms.h
@@ -56,7 +56,6 @@ public:
     Xcb::Atom net_wm_sync_request_counter;
     Xcb::Atom net_wm_sync_request;
     Xcb::Atom kde_net_wm_shadow;
-    Xcb::Atom kde_first_in_window_list;
     Xcb::Atom kde_color_sheme;
     Xcb::Atom kde_skip_close_animation;
     Xcb::Atom kde_screen_edge_show;
diff --git a/src/events.cpp b/src/events.cpp
index 813c92c7e1..effef23707 100644
--- a/src/events.cpp
+++ b/src/events.cpp
@@ -674,8 +674,6 @@ void X11Window::propertyNotifyEvent(xcb_property_notify_event_t *e)
             getSyncCounter();
         } else if (e->atom == atoms->activities) {
             checkActivities();
-        } else if (e->atom == atoms->kde_first_in_window_list) {
-            updateFirstInTabBox();
         } else if (e->atom == atoms->kde_color_sheme) {
             updateColorScheme();
         } else if (e->atom == atoms->kde_screen_edge_show) {
diff --git a/src/tabbox/clientmodel.cpp b/src/tabbox/clientmodel.cpp
index 79241d9302..565d633ea4 100644
--- a/src/tabbox/clientmodel.cpp
+++ b/src/tabbox/clientmodel.cpp
@@ -70,8 +70,7 @@ QVariant ClientModel::data(const QModelIndex &index, int role) const
     case MinimizedRole:
         return client->isMinimized();
     case CloseableRole:
-        // clients that claim to be first are not closeable
-        return client->isCloseable() && !client->isFirstInTabBox();
+        return client->isCloseable();
     case IconRole:
         return client->icon();
     default:
@@ -155,8 +154,7 @@ void ClientModel::createClientList(bool partialReset)
     createClientList(tabBox->currentDesktop(), partialReset);
 }
 
-void ClientModel::createFocusChainClientList(int desktop,
-                                             const std::shared_ptr<TabBoxClient> &start, TabBoxClientList &stickyClients)
+void ClientModel::createFocusChainClientList(int desktop, const std::shared_ptr<TabBoxClient> &start)
 {
     auto c = start;
     if (!tabBox->isInFocusChain(c.get())) {
@@ -170,16 +168,12 @@ void ClientModel::createFocusChainClientList(int desktop,
         std::shared_ptr<TabBoxClient> add = tabBox->clientToAddToList(c.get(), desktop).lock();
         if (add) {
             m_mutableClientList += add;
-            if (add->isFirstInTabBox()) {
-                stickyClients << add;
-            }
         }
         c = tabBox->nextClientFocusChain(c.get()).lock();
     } while (c && c != stop);
 }
 
-void ClientModel::createStackingOrderClientList(int desktop,
-                                                const std::shared_ptr<TabBoxClient> &start, TabBoxClientList &stickyClients)
+void ClientModel::createStackingOrderClientList(int desktop, const std::shared_ptr<TabBoxClient> &start)
 {
     // TODO: needs improvement
     const TabBoxClientList stacking = tabBox->stackingOrder();
@@ -198,9 +192,6 @@ void ClientModel::createStackingOrderClientList(int desktop,
             } else {
                 m_mutableClientList += add;
             }
-            if (add->isFirstInTabBox()) {
-                stickyClients << add;
-            }
         }
         if (index >= stacking.size() - 1) {
             c = nullptr;
@@ -226,15 +217,14 @@ void ClientModel::createClientList(int desktop, bool partialReset)
     }
 
     m_mutableClientList.clear();
-    TabBoxClientList stickyClients;
 
     switch (tabBox->config().clientSwitchingMode()) {
     case TabBoxConfig::FocusChainSwitching: {
-        createFocusChainClientList(desktop, start, stickyClients);
+        createFocusChainClientList(desktop, start);
         break;
     }
     case TabBoxConfig::StackingOrderSwitching: {
-        createStackingOrderClientList(desktop, start, stickyClients);
+        createStackingOrderClientList(desktop, start);
         break;
     }
     }
@@ -246,13 +236,6 @@ void ClientModel::createClientList(int desktop, bool partialReset)
         });
     }
 
-    for (const std::weak_ptr<TabBoxClient> &c : std::as_const(stickyClients)) {
-        m_mutableClientList.erase(std::remove_if(m_mutableClientList.begin(), m_mutableClientList.end(), [c = c.lock()](auto &client) {
-                                      return client.lock() == c;
-                                  }),
-                                  m_mutableClientList.end());
-        m_mutableClientList.prepend(c);
-    }
     if (tabBox->config().clientApplicationsMode() != TabBoxConfig::AllWindowsCurrentApplication
         && (tabBox->config().showDesktopMode() == TabBoxConfig::ShowDesktopClient || m_mutableClientList.isEmpty())) {
         std::weak_ptr<TabBoxClient> desktopClient = tabBox->desktopClient();
diff --git a/src/tabbox/clientmodel.h b/src/tabbox/clientmodel.h
index 5f56f8b330..90d7f53ec8 100644
--- a/src/tabbox/clientmodel.h
+++ b/src/tabbox/clientmodel.h
@@ -93,10 +93,8 @@ public Q_SLOTS:
     void activate(int index);
 
 private:
-    void createFocusChainClientList(int desktop, const std::shared_ptr<TabBoxClient> &start,
-                                    TabBoxClientList &stickyClients);
-    void createStackingOrderClientList(int desktop, const std::shared_ptr<TabBoxClient> &start,
-                                       TabBoxClientList &stickyClients);
+    void createFocusChainClientList(int desktop, const std::shared_ptr<TabBoxClient> &start);
+    void createStackingOrderClientList(int desktop, const std::shared_ptr<TabBoxClient> &start);
 
     TabBoxClientList m_clientList;
     TabBoxClientList m_mutableClientList;
diff --git a/src/tabbox/tabbox.cpp b/src/tabbox/tabbox.cpp
index 093ea1e41c..cbbcb54691 100644
--- a/src/tabbox/tabbox.cpp
+++ b/src/tabbox/tabbox.cpp
@@ -390,11 +390,6 @@ void TabBoxClientImpl::close()
     m_client->closeWindow();
 }
 
-bool TabBoxClientImpl::isFirstInTabBox() const
-{
-    return m_client->isFirstInTabBox();
-}
-
 QUuid TabBoxClientImpl::internalId() const
 {
     return m_client->internalId();
diff --git a/src/tabbox/tabbox.h b/src/tabbox/tabbox.h
index fbd89c3e07..fc7699cd01 100644
--- a/src/tabbox/tabbox.h
+++ b/src/tabbox/tabbox.h
@@ -84,7 +84,6 @@ public:
     int height() const override;
     bool isCloseable() const override;
     void close() override;
-    bool isFirstInTabBox() const override;
     QUuid internalId() const override;
 
     Window *client() const
diff --git a/src/tabbox/tabboxhandler.h b/src/tabbox/tabboxhandler.h
index c492086fdd..ae38b74690 100644
--- a/src/tabbox/tabboxhandler.h
+++ b/src/tabbox/tabboxhandler.h
@@ -334,7 +334,6 @@ public:
     virtual int height() const = 0;
     virtual bool isCloseable() const = 0;
     virtual void close() = 0;
-    virtual bool isFirstInTabBox() const = 0;
     virtual QUuid internalId() const = 0;
 };
 
diff --git a/src/window.h b/src/window.h
index 5b20829fad..f7b3a18fcf 100644
--- a/src/window.h
+++ b/src/window.h
@@ -825,10 +825,6 @@ public:
     {
         return m_tabBoxClient;
     }
-    bool isFirstInTabBox() const
-    {
-        return m_firstInTabBox;
-    }
     bool skipSwitcher() const
     {
         return m_skipSwitcher;
@@ -1563,10 +1559,6 @@ protected:
 
 protected:
     Window();
-    void setFirstInTabBox(bool enable)
-    {
-        m_firstInTabBox = enable;
-    }
     void setIcon(const QIcon &icon);
     void startAutoRaise();
     void autoRaise();
@@ -1895,7 +1887,6 @@ private:
     QRectF ensureSpecialStateGeometry(const QRectF &geometry);
 
     std::shared_ptr<TabBox::TabBoxClientImpl> m_tabBoxClient;
-    bool m_firstInTabBox = false;
     bool m_skipTaskbar = false;
     /**
      * Unaffected by KWin
diff --git a/src/x11window.cpp b/src/x11window.cpp
index ce1056482a..6504dae650 100644
--- a/src/x11window.cpp
+++ b/src/x11window.cpp
@@ -495,7 +495,6 @@ bool X11Window::manage(xcb_window_t w, bool isMapped)
     auto skipCloseAnimationCookie = fetchSkipCloseAnimation();
     auto showOnScreenEdgeCookie = fetchShowOnScreenEdge();
     auto colorSchemeCookie = fetchPreferredColorScheme();
-    auto firstInTabBoxCookie = fetchFirstInTabBox();
     auto transientCookie = fetchTransient();
     auto activitiesCookie = fetchActivities();
     auto applicationMenuServiceNameCookie = fetchApplicationMenuServiceName();
@@ -561,7 +560,6 @@ bool X11Window::manage(xcb_window_t w, bool isMapped)
     setOriginalSkipTaskbar((info->state() & NET::SkipTaskbar) != 0);
     setSkipPager((info->state() & NET::SkipPager) != 0);
     setSkipSwitcher((info->state() & NET::SkipSwitcher) != 0);
-    readFirstInTabBox(firstInTabBoxCookie);
 
     setupCompositing();
 
@@ -2569,24 +2567,6 @@ void X11Window::setSessionActivityOverride(bool needed)
     updateActivities(false);
 }
 
-Xcb::Property X11Window::fetchFirstInTabBox() const
-{
-    return Xcb::Property(false, m_client, atoms->kde_first_in_window_list,
-                         atoms->kde_first_in_window_list, 0, 1);
-}
-
-void X11Window::readFirstInTabBox(Xcb::Property &property)
-{
-    setFirstInTabBox(property.toBool(32, atoms->kde_first_in_window_list));
-}
-
-void X11Window::updateFirstInTabBox()
-{
-    // TODO: move into KWindowInfo
-    Xcb::Property property = fetchFirstInTabBox();
-    readFirstInTabBox(property);
-}
-
 Xcb::StringProperty X11Window::fetchPreferredColorScheme() const
 {
     return Xcb::StringProperty(m_client, atoms->kde_color_sheme);
diff --git a/src/x11window.h b/src/x11window.h
index 855db627c0..385ff61029 100644
--- a/src/x11window.h
+++ b/src/x11window.h
@@ -241,9 +241,6 @@ public:
 
     bool isClientSideDecorated() const;
 
-    Xcb::Property fetchFirstInTabBox() const;
-    void readFirstInTabBox(Xcb::Property &property);
-    void updateFirstInTabBox();
     Xcb::StringProperty fetchPreferredColorScheme() const;
     QString readPreferredColorScheme(Xcb::StringProperty &property) const;
     QString preferredColorScheme() const override;