diff --git a/src/wxmac/src/mac/wxMacDC.cc b/src/wxmac/src/mac/wxMacDC.cc
index b3af74a244..418a930503 100644
--- a/src/wxmac/src/mac/wxMacDC.cc
+++ b/src/wxmac/src/mac/wxMacDC.cc
@@ -24,6 +24,7 @@ wxMacDC::wxMacDC(CGrafPtr port)
 //-----------------------------------------------------------------------------
 wxMacDC::~wxMacDC(void)	// destructor
 {
+  cCurrentUser = NULL;
 }
 
 //-----------------------------------------------------------------------------
diff --git a/src/wxmac/src/mac/wx_menu.cc b/src/wxmac/src/mac/wx_menu.cc
index b7c07b4eaf..1ac65708d5 100644
--- a/src/wxmac/src/mac/wx_menu.cc
+++ b/src/wxmac/src/mac/wx_menu.cc
@@ -194,11 +194,13 @@ wxMenu::~wxMenu(void)
   wxNode* node;
   wxMenuItem* item;
 
-  if (menu_bar) // may have to remove menu from the current mac menu bar
-    {
-      menu_bar->Delete(this);
-    } else if (window_parent)
-      ((wxMenu *)window_parent)->Delete(this, 0, -1);
+  if (menu_bar) { // may have to remove menu from the current mac menu bar
+    menu_bar->Delete(this);
+    menu_bar = NULL;
+  } else if (window_parent) {
+    ((wxMenu *)window_parent)->Delete(this, 0, -1);
+    window_parent = NULL;
+  }
 
   ::DisposeMenu(cMacMenu); // does not dispose of submenus
 
diff --git a/src/wxmac/src/mac/wx_print.cc b/src/wxmac/src/mac/wx_print.cc
index 4bf1df93fa..f73c31752f 100644
--- a/src/wxmac/src/mac/wx_print.cc
+++ b/src/wxmac/src/mac/wx_print.cc
@@ -115,11 +115,15 @@ wxPrintData::wxPrintData(void)
 
 wxPrintData::~wxPrintData(void)
 {
-  if (cPrintSettings)
+  if (cPrintSettings) {
     PMRelease(cPrintSettings);
+    cPrintSettings = NULL;
+  }
 
-  if (cPageFormat)
+  if (cPageFormat) {
     PMRelease(cPageFormat);
+    cPageFormat = NULL;
+  }
 
   if (cPrintSession) {
     PMRelease(cPrintSession);
diff --git a/src/wxmac/src/mac/wx_win.cc b/src/wxmac/src/mac/wx_win.cc
index d0ac105e45..b4fed99785 100644
--- a/src/wxmac/src/mac/wx_win.cc
+++ b/src/wxmac/src/mac/wx_win.cc
@@ -363,6 +363,11 @@ wxWindow::~wxWindow(void) // Destructor
     DisposeControl(cPaintControl);
     cPaintControl = NULL;
   }
+
+  /* Must zero out fieldsd that are WXGC_IGNOREd: */
+  cParentArea = NULL;
+  cMacDC = NULL;
+  window_parent = NULL;
 }
 
 //=============================================================================
diff --git a/src/wxwindow/src/base/wb_item.cxx b/src/wxwindow/src/base/wb_item.cxx
index b23e0011b2..aede1ff657 100644
--- a/src/wxwindow/src/base/wb_item.cxx
+++ b/src/wxwindow/src/base/wb_item.cxx
@@ -153,6 +153,8 @@ wxbMenu::wxbMenu (char *Title, wxFunction WXUNUSED(func))
 // The wxWindow destructor will take care of deleting the submenus.
 wxbMenu::~wxbMenu (void)
 {
+  menu_bar= NULL;
+  top_level_menu = NULL;
 }
 
 wxMenuItem *wxbMenu::FindItemForId (long itemId, wxMenu ** itemMenu, int * pos)
@@ -252,6 +254,7 @@ wxbMenuBar::wxbMenuBar (int N, wxMenu * Menus[], char *Titles[])
 
 wxbMenuBar::~wxbMenuBar (void)
 {
+  menu_bar_frame = NULL;
 }
 
 void wxbMenuBar::Append (wxMenu * menu, char *title)
diff --git a/src/wxwindow/src/msw/wx_choic.cxx b/src/wxwindow/src/msw/wx_choic.cxx
index 1a1ece0176..2f3a08f440 100644
--- a/src/wxwindow/src/msw/wx_choic.cxx
+++ b/src/wxwindow/src/msw/wx_choic.cxx
@@ -466,6 +466,7 @@ wxCombo::wxCombo(wxWindow *for_canvas,
 
 wxCombo::~wxCombo(void)
 {
+  forCanvas = NULL;
 }
 
 Bool wxCombo::PreOnEvent(wxWindow *win, wxMouseEvent *e)