diff --git a/layers.cpp b/layers.cpp
index 46dd76354f..ca244c089d 100644
--- a/layers.cpp
+++ b/layers.cpp
@@ -331,7 +331,7 @@ void Workspace::lowerClient(AbstractClient* c, bool nogroup)
         most_recently_raised = 0;
 }
 
-void Workspace::lowerClientWithinApplication(Client* c)
+void Workspace::lowerClientWithinApplication(AbstractClient* c)
 {
     if (!c)
         return;
@@ -346,11 +346,11 @@ void Workspace::lowerClientWithinApplication(Client* c)
     for (ToplevelList::Iterator it = unconstrained_stacking_order.begin();
             it != unconstrained_stacking_order.end();
             ++it) {
-        Client *client = qobject_cast<Client*>(*it);
+        AbstractClient *client = qobject_cast<AbstractClient*>(*it);
         if (!client) {
             continue;
         }
-        if (Client::belongToSameApplication(client, c)) {
+        if (AbstractClient::belongToSameApplication(client, c)) {
             unconstrained_stacking_order.insert(it, c);
             lowered = true;
             break;
diff --git a/workspace.h b/workspace.h
index f2ab232202..2cd76a12ca 100644
--- a/workspace.h
+++ b/workspace.h
@@ -484,7 +484,7 @@ private:
     void propagateClients(bool propagate_new_clients);   // Called only from updateStackingOrder
     ToplevelList constrainedStackingOrder();
     void raiseClientWithinApplication(Client* c);
-    void lowerClientWithinApplication(Client* c);
+    void lowerClientWithinApplication(AbstractClient* c);
     bool allowFullClientRaising(const AbstractClient* c, xcb_timestamp_t timestamp);
     bool keepTransientAbove(const AbstractClient* mainwindow, const AbstractClient* transient);
     void blockStackingUpdates(bool block);