diff --git a/abstract_client.h b/abstract_client.h
index 795faea33..a6572113d 100644
--- a/abstract_client.h
+++ b/abstract_client.h
@@ -71,6 +71,7 @@ public:
     virtual void setOnAllDesktops(bool set) = 0;
     virtual void setDesktop(int) = 0;
     virtual void minimize(bool avoid_animation = false) = 0;
+    virtual void unminimize(bool avoid_animation = false)= 0;
     virtual void setFullScreen(bool set, bool user = true) = 0;
     virtual bool keepAbove() const = 0;
     virtual void setKeepAbove(bool) = 0;
diff --git a/activation.cpp b/activation.cpp
index 5ceee9080..5bb3a73d6 100644
--- a/activation.cpp
+++ b/activation.cpp
@@ -287,7 +287,7 @@ void Workspace::setActiveClient(Client* c)
 
   \sa stActiveClient(), requestFocus()
  */
-void Workspace::activateClient(Client* c, bool force)
+void Workspace::activateClient(AbstractClient* c, bool force)
 {
     if (c == NULL) {
         focusToNull();
@@ -322,7 +322,10 @@ void Workspace::activateClient(Client* c, bool force)
     // E.g. typing URL in minicli which will show kio_uiserver dialog (with workaround),
     // and then kdesktop shows dialog about SSL certificate.
     // This needs also avoiding user creation time in Client::readUserTimeMapTimestamp().
-    c->updateUserTime();
+    if (Client *client = dynamic_cast<Client*>(c)) {
+        // updateUserTime is X11 specific
+        client->updateUserTime();
+    }
 }
 
 /*!
@@ -332,9 +335,9 @@ void Workspace::activateClient(Client* c, bool force)
 
   \sa Workspace::activateClient()
  */
-void Workspace::requestFocus(Client* c, bool force)
+void Workspace::requestFocus(AbstractClient* c, bool force)
 {
-    takeActivity(c, force ? ActivityFocusForce : ActivityFocus);
+    takeActivity(dynamic_cast<Client*>(c), force ? ActivityFocusForce : ActivityFocus);
 }
 
 void Workspace::takeActivity(Client* c, ActivityFlags flags)
diff --git a/client.h b/client.h
index 13f57af70..d5ea957f3 100644
--- a/client.h
+++ b/client.h
@@ -538,7 +538,7 @@ public:
 
     void setMinimized(bool set);
     void minimize(bool avoid_animation = false) override;
-    void unminimize(bool avoid_animation = false);
+    void unminimize(bool avoid_animation = false) override;
     void killWindow();
     void maximize(MaximizeMode) override;
     void toggleShade();
diff --git a/workspace.h b/workspace.h
index ff3a9be05..906c5a202 100644
--- a/workspace.h
+++ b/workspace.h
@@ -148,8 +148,8 @@ public:
 
     Client* clientUnderMouse(int screen) const;
 
-    void activateClient(Client*, bool force = false);
-    void requestFocus(Client* c, bool force = false);
+    void activateClient(AbstractClient*, bool force = false);
+    void requestFocus(AbstractClient* c, bool force = false);
     enum ActivityFlag {
         ActivityFocus = 1 << 0, // focus the window
         ActivityFocusForce = 1 << 1 | ActivityFocus, // focus even if Dock etc.