diff --git a/src/univ/themes/mono.cpp b/src/univ/themes/mono.cpp
index 3c6ef714ba..d9ca82895d 100644
--- a/src/univ/themes/mono.cpp
+++ b/src/univ/themes/mono.cpp
@@ -29,6 +29,7 @@
 #if wxUSE_THEME_MONO
 
 #ifndef WX_PRECOMP
+    #include "wx/window.h"
     #include "wx/dc.h"
 #endif // WX_PRECOMP