diff --git a/src/workspace.cpp b/src/workspace.cpp
index 1cf81241ee..67ee32912a 100644
--- a/src/workspace.cpp
+++ b/src/workspace.cpp
@@ -1859,14 +1859,9 @@ void Workspace::forEachToplevel(std::function<void (Toplevel *)> func)
 
 bool Workspace::hasClient(const AbstractClient *c)
 {
-    if (auto cc = dynamic_cast<const X11Client *>(c)) {
-        return hasClient(cc);
-    } else {
-        return findAbstractClient([c](const AbstractClient *test) {
-            return test == c;
-        }) != nullptr;
-    }
-    return false;
+    return findAbstractClient([&c](const AbstractClient *test) {
+        return test == c;
+    }) != nullptr;
 }
 
 void Workspace::forEachAbstractClient(std::function< void (AbstractClient*) > func)
diff --git a/src/workspace.h b/src/workspace.h
index 352638b52d..decd8f50e0 100644
--- a/src/workspace.h
+++ b/src/workspace.h
@@ -71,7 +71,6 @@ public:
     bool workspaceEvent(xcb_generic_event_t*);
     bool workspaceEvent(QEvent*);
 
-    bool hasClient(const X11Client *);
     bool hasClient(const AbstractClient*);
 
     /**
@@ -791,13 +790,6 @@ void Workspace::forEachUnmanaged(std::function< void (Unmanaged*) > func)
     std::for_each(m_unmanaged.constBegin(), m_unmanaged.constEnd(), func);
 }
 
-inline bool Workspace::hasClient(const X11Client *c)
-{
-    return findClient([c](const X11Client *test) {
-        return test == c;
-    });
-}
-
 inline Workspace *workspace()
 {
     return Workspace::_self;