diff --git a/abstract_client.cpp b/abstract_client.cpp
index c78223f71..1d788c2f3 100644
--- a/abstract_client.cpp
+++ b/abstract_client.cpp
@@ -38,4 +38,9 @@ bool AbstractClient::belongToSameApplication(const AbstractClient *c1, const Abs
     return c1->belongsToSameApplication(c2, active_hack);
 }
 
+bool AbstractClient::isTransient() const
+{
+    return false;
+}
+
 }
diff --git a/abstract_client.h b/abstract_client.h
index 9369e08ce..71727b0a6 100644
--- a/abstract_client.h
+++ b/abstract_client.h
@@ -47,6 +47,15 @@ public:
     virtual bool wantsTabFocus() const = 0;
     virtual bool isFullScreen() const = 0;
     virtual const QIcon &icon() const = 0;
+    virtual void cancelAutoRaise() = 0;
+    virtual bool isTransient() const;
+    /**
+     * Returns true for "special" windows and false for windows which are "normal"
+     * (normal=window which has a border, can be moved by the user, can be closed, etc.)
+     * true for Desktop, Dock, Splash, Override and TopMenu (and Toolbar??? - for now)
+     * false for Normal, Dialog, Utility and Menu (and Toolbar??? - not yet) TODO
+     */
+    virtual bool isSpecialWindow() const = 0;
 
     // TODO: remove boolean trap
     static bool belongToSameApplication(const AbstractClient* c1, const AbstractClient* c2, bool active_hack = false);
diff --git a/client.h b/client.h
index 323722192..1293021db 100644
--- a/client.h
+++ b/client.h
@@ -295,7 +295,7 @@ public:
 
     const Client* transientFor() const;
     Client* transientFor();
-    bool isTransient() const;
+    bool isTransient() const override;
     bool groupTransient() const;
     bool wasOriginallyGroupTransient() const;
     ClientList mainClients() const; // Call once before loop , is not indirect
@@ -321,7 +321,7 @@ public:
      * true for Desktop, Dock, Splash, Override and TopMenu (and Toolbar??? - for now)
      * false for Normal, Dialog, Utility and Menu (and Toolbar??? - not yet) TODO
      */
-    bool isSpecialWindow() const;
+    bool isSpecialWindow() const override;
     bool hasNETSupport() const;
 
     QSize minSize() const;
@@ -544,7 +544,7 @@ public:
     void toggleShade();
     void showContextHelp();
     void cancelShadeHoverTimer();
-    void cancelAutoRaise();
+    void cancelAutoRaise() override;
     void checkActiveModal();
     StrutRect strutRect(StrutArea area) const;
     StrutRects strutRects() const;
diff --git a/layers.cpp b/layers.cpp
index fd33afe2e..49cc67830 100644
--- a/layers.cpp
+++ b/layers.cpp
@@ -281,10 +281,10 @@ Client* Workspace::findDesktop(bool topmost, int desktop) const
     return NULL;
 }
 
-void Workspace::raiseOrLowerClient(Client *c)
+void Workspace::raiseOrLowerClient(AbstractClient *c)
 {
     if (!c) return;
-    Client* topmost = NULL;
+    AbstractClient* topmost = NULL;
 // TODO    Q_ASSERT( block_stacking_updates == 0 );
     if (most_recently_raised && stacking_order.contains(most_recently_raised) &&
             most_recently_raised->isShown(true) && c->isOnCurrentDesktop())
@@ -300,7 +300,7 @@ void Workspace::raiseOrLowerClient(Client *c)
 }
 
 
-void Workspace::lowerClient(Client* c, bool nogroup)
+void Workspace::lowerClient(AbstractClient* c, bool nogroup)
 {
     if (!c)
         return;
@@ -313,7 +313,7 @@ void Workspace::lowerClient(Client* c, bool nogroup)
     unconstrained_stacking_order.prepend(c);
     if (!nogroup && c->isTransient()) {
         // lower also all windows in the group, in their reversed stacking order
-        ClientList wins = ensureStackingOrder(c->group()->members());
+        ClientList wins = ensureStackingOrder(static_cast<Client*>(c)->group()->members());
         for (int i = wins.size() - 1;
                 i >= 0;
                 --i) {
@@ -356,7 +356,7 @@ void Workspace::lowerClientWithinApplication(Client* c)
     // ignore mainwindows
 }
 
-void Workspace::raiseClient(Client* c, bool nogroup)
+void Workspace::raiseClient(AbstractClient* c, bool nogroup)
 {
     if (!c)
         return;
@@ -367,7 +367,7 @@ void Workspace::raiseClient(Client* c, bool nogroup)
 
     if (!nogroup && c->isTransient()) {
         ClientList transients;
-        Client *transient_parent = c;
+        Client *transient_parent = static_cast<Client*>(c);
         while ((transient_parent = transient_parent->transientFor()))
             transients << transient_parent;
         foreach (transient_parent, transients)
diff --git a/workspace.h b/workspace.h
index 71daad654..210f6d9a6 100644
--- a/workspace.h
+++ b/workspace.h
@@ -174,14 +174,14 @@ public:
 
     QPoint adjustClientPosition(Client* c, QPoint pos, bool unrestricted, double snapAdjust = 1.0);
     QRect adjustClientSize(Client* c, QRect moveResizeGeom, int mode);
-    void raiseClient(Client* c, bool nogroup = false);
-    void lowerClient(Client* c, bool nogroup = false);
+    void raiseClient(AbstractClient* c, bool nogroup = false);
+    void lowerClient(AbstractClient* c, bool nogroup = false);
     void raiseClientRequest(Client* c, NET::RequestSource src, xcb_timestamp_t timestamp);
     void lowerClientRequest(Client* c, NET::RequestSource src, xcb_timestamp_t timestamp);
     void restackClientUnderActive(Client*);
     void restack(AbstractClient *c, AbstractClient *under, bool force = false);
     void updateClientLayer(Client* c);
-    void raiseOrLowerClient(Client*);
+    void raiseOrLowerClient(AbstractClient*);
     void resetUpdateToolWindowsTimer();
     void restoreSessionStackingOrder(Client* c);
     void updateStackingOrder(bool propagate_new_clients = false);
@@ -515,7 +515,7 @@ private:
 
     Client* active_client;
     Client* last_active_client;
-    Client* most_recently_raised; // Used ONLY by raiseOrLowerClient()
+    AbstractClient* most_recently_raised; // Used ONLY by raiseOrLowerClient()
     Client* movingClient;
 
     // Delay(ed) window focus timer and client