diff --git a/src/gtk/window.cpp b/src/gtk/window.cpp
index b9df8d107b..623abc1151 100644
--- a/src/gtk/window.cpp
+++ b/src/gtk/window.cpp
@@ -248,6 +248,8 @@ void debug_focus_in( GtkWidget* widget, const wxChar* name, const wxChar *window
     }
 }
 
+#else
+#define DEBUG_MAIN_THREAD
 #endif // Debug
 
 //-----------------------------------------------------------------------------
diff --git a/src/gtk1/window.cpp b/src/gtk1/window.cpp
index b9df8d107b..623abc1151 100644
--- a/src/gtk1/window.cpp
+++ b/src/gtk1/window.cpp
@@ -248,6 +248,8 @@ void debug_focus_in( GtkWidget* widget, const wxChar* name, const wxChar *window
     }
 }
 
+#else
+#define DEBUG_MAIN_THREAD
 #endif // Debug
 
 //-----------------------------------------------------------------------------