diff --git a/src/keyboard_input.cpp b/src/keyboard_input.cpp
index 715d2dc5cc..65145a8a00 100644
--- a/src/keyboard_input.cpp
+++ b/src/keyboard_input.cpp
@@ -209,6 +209,7 @@ Window *KeyboardInputRedirection::pickFocus() const
                 return t;
             } while (it != stacking.begin());
         }
+        return nullptr;
     }
 
     if (input()->isSelectingWindow()) {