diff --git a/debug_console.cpp b/debug_console.cpp
--- a/debug_console.cpp
+++ b/debug_console.cpp
@@ -899,8 +899,10 @@
         m_x11Clients.append(c);
     }
     connect(workspace(), &Workspace::clientAdded, this,
-        [this] (X11Client *c) {
-            add(s_x11ClientId -1, m_x11Clients, c);
+        [this] (AbstractClient *client) {
+            if (X11Client *x11Client = qobject_cast<X11Client *>(client)) {
+                add(s_x11ClientId -1, m_x11Clients, x11Client);
+            }
         }
     );
     connect(workspace(), &Workspace::clientRemoved, this,
diff --git a/effects.cpp b/effects.cpp
--- a/effects.cpp
+++ b/effects.cpp
@@ -166,7 +166,7 @@
         }
     );
     connect(ws, &Workspace::clientAdded, this,
-        [this](X11Client *c) {
+        [this](AbstractClient *c) {
             if (c->readyForPainting())
                 slotClientShown(c);
             else
@@ -564,8 +564,8 @@
 
 void EffectsHandlerImpl::slotClientShown(KWin::Toplevel *t)
 {
-    Q_ASSERT(qobject_cast<X11Client *>(t));
-    X11Client *c = static_cast<X11Client *>(t);
+    Q_ASSERT(qobject_cast<AbstractClient *>(t));
+    AbstractClient *c = static_cast<AbstractClient *>(t);
     disconnect(c, &Toplevel::windowShown, this, &EffectsHandlerImpl::slotClientShown);
     setupClientConnections(c);
     emit windowAdded(c->effectWindow());
diff --git a/scripting/workspace_wrapper.h b/scripting/workspace_wrapper.h
--- a/scripting/workspace_wrapper.h
+++ b/scripting/workspace_wrapper.h
@@ -351,8 +351,7 @@
     void hideOutline();
 
 private Q_SLOTS:
-    void setupAbstractClientConnections(AbstractClient *client);
-    void setupClientConnections(X11Client *client);
+    void setupClientConnections(AbstractClient *client);
 };
 
 class QtScriptWorkspaceWrapper : public WorkspaceWrapper
diff --git a/scripting/workspace_wrapper.cpp b/scripting/workspace_wrapper.cpp
--- a/scripting/workspace_wrapper.cpp
+++ b/scripting/workspace_wrapper.cpp
@@ -69,7 +69,7 @@
     connect(QApplication::desktop(), SIGNAL(resized(int)), SIGNAL(screenResized(int)));
     if (waylandServer()) {
         connect(waylandServer(), &WaylandServer::shellClientAdded, this, &WorkspaceWrapper::clientAdded);
-        connect(waylandServer(), &WaylandServer::shellClientAdded, this, &WorkspaceWrapper::setupAbstractClientConnections);
+        connect(waylandServer(), &WaylandServer::shellClientAdded, this, &WorkspaceWrapper::setupClientConnections);
     }
     foreach (KWin::X11Client *client, ws->clientList()) {
         setupClientConnections(client);
@@ -277,20 +277,19 @@
     return Workspace::self()->supportInformation();
 }
 
-void WorkspaceWrapper::setupAbstractClientConnections(AbstractClient *client)
+void WorkspaceWrapper::setupClientConnections(AbstractClient *client)
 {
     connect(client, &AbstractClient::clientMinimized, this, &WorkspaceWrapper::clientMinimized);
     connect(client, &AbstractClient::clientUnminimized, this, &WorkspaceWrapper::clientUnminimized);
     connect(client, qOverload<AbstractClient *, bool, bool>(&AbstractClient::clientMaximizedStateChanged),
             this, &WorkspaceWrapper::clientMaximizeSet);
-}
 
-void WorkspaceWrapper::setupClientConnections(X11Client *client)
-{
-    setupAbstractClientConnections(client);
+    X11Client *x11Client = qobject_cast<X11Client *>(client); // TODO: Drop X11-specific signals.
+    if (!x11Client)
+        return;
 
-    connect(client, &X11Client::clientManaging, this, &WorkspaceWrapper::clientManaging);
-    connect(client, &X11Client::clientFullScreenSet, this, &WorkspaceWrapper::clientFullScreenSet);
+    connect(x11Client, &X11Client::clientManaging, this, &WorkspaceWrapper::clientManaging);
+    connect(x11Client, &X11Client::clientFullScreenSet, this, &WorkspaceWrapper::clientFullScreenSet);
 }
 
 void WorkspaceWrapper::showOutline(const QRect &geometry)
diff --git a/workspace.h b/workspace.h
--- a/workspace.h
+++ b/workspace.h
@@ -502,7 +502,7 @@
     //Signals required for the scripting interface
     void desktopPresenceChanged(KWin::AbstractClient*, int);
     void currentDesktopChanged(int, KWin::AbstractClient*);
-    void clientAdded(KWin::X11Client *);
+    void clientAdded(KWin::AbstractClient *);
     void clientRemoved(KWin::AbstractClient*);
     void clientActivated(KWin::AbstractClient*);
     void clientDemandsAttentionChanged(KWin::AbstractClient*, bool);