diff --git a/source/utils/CarlaPluginUI.cpp b/source/utils/CarlaPluginUI.cpp
index 2efc2e5b6..722bbc4b7 100644
--- a/source/utils/CarlaPluginUI.cpp
+++ b/source/utils/CarlaPluginUI.cpp
@@ -567,6 +567,11 @@ public:
         [fWindow makeKeyWindow];
     }
 
+    void setChildWindow(void* const winId) override
+    {
+        CARLA_SAFE_ASSERT_RETURN(winId != nullptr,);
+    }
+
     void* getPtr() const noexcept override
     {
         return (void*)fView;
@@ -767,6 +772,11 @@ public:
         // TODO
     }
 
+    void setChildWindow(void* const winId) override
+    {
+        CARLA_SAFE_ASSERT_RETURN(winId != nullptr,);
+    }
+
     void* getPtr() const noexcept override
     {
         return (void*)fWindow;