diff --git a/src/mac/carbon/toplevel.cpp b/src/mac/carbon/toplevel.cpp
index f3f0878937..7eb06cda37 100644
--- a/src/mac/carbon/toplevel.cpp
+++ b/src/mac/carbon/toplevel.cpp
@@ -970,6 +970,10 @@ wxTopLevelWindowMac::~wxTopLevelWindowMac()
     FullScreenData *data = (FullScreenData *) m_macFullScreenData ;
     delete data ;
     m_macFullScreenData = NULL ;
+
+    // avoid dangling refs
+    if ( s_macDeactivateWindow == this )
+        s_macDeactivateWindow = NULL;
 }