diff --git a/contrib/include/wx/gizmos/dynamicsash.h b/contrib/include/wx/gizmos/dynamicsash.h
index 617463e76c..2d5da5c8b0 100644
--- a/contrib/include/wx/gizmos/dynamicsash.h
+++ b/contrib/include/wx/gizmos/dynamicsash.h
@@ -15,6 +15,11 @@
 
 #include "wx/gizmos/gizmos.h"
 
+#if !wxUSE_MDI
+#    error "wxUSE_MDI must be defined for gizmos to compile."
+#endif /* !wxUSE_MDI */
+
+
 /*
 
     wxDynamicSashWindow
diff --git a/contrib/src/gizmos/dynamicsash.cpp b/contrib/src/gizmos/dynamicsash.cpp
index 137d00cc4e..527f103cdd 100644
--- a/contrib/src/gizmos/dynamicsash.cpp
+++ b/contrib/src/gizmos/dynamicsash.cpp
@@ -13,6 +13,8 @@
 // For compilers that support precompilation, includes "wx/wx.h".
 #include "wx/wxprec.h"
 
+#if !wxUSE_MDI
+
 #ifdef __BORLANDC__
     #pragma hdrstop
 #endif
@@ -1469,3 +1471,4 @@ wxDynamicSashReparentEvent::wxDynamicSashReparentEvent(const wxDynamicSashRepare
 
 IMPLEMENT_DYNAMIC_CLASS(wxDynamicSashReparentEvent, wxEvent)
 
+#endif  // !wxUSE_MDI
\ No newline at end of file