diff --git a/placement.cpp b/placement.cpp
index 13b7ae4476..42e2ffa510 100644
--- a/placement.cpp
+++ b/placement.cpp
@@ -497,7 +497,7 @@ void Placement::placeDialog(Client* c, QRect& area, Policy nextPlacement)
     placeOnMainWindow(c, area, nextPlacement);
 }
 
-void Placement::placeUnderMouse(Client* c, QRect& area, Policy /*next*/)
+void Placement::placeUnderMouse(AbstractClient* c, QRect& area, Policy /*next*/)
 {
     area = checkArea(c, area);
     QRect geom = c->geometry();
diff --git a/placement.h b/placement.h
index ce0fdf6596..fd12cfc7e4 100644
--- a/placement.h
+++ b/placement.h
@@ -90,7 +90,7 @@ public:
 
 private:
     void place(Client* c, QRect& area, Policy policy, Policy nextPlacement = Unknown);
-    void placeUnderMouse(Client* c, QRect& area, Policy next = Unknown);
+    void placeUnderMouse(AbstractClient* c, QRect& area, Policy next = Unknown);
     void placeOnMainWindow(Client* c, QRect& area, Policy next = Unknown);
     QRect checkArea(const AbstractClient*c, const QRect& area);