fix crash after destroying a default button in a backwards compatible way (patch 1727956)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@46272 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -91,16 +91,9 @@ Major new features in 2.8 release
 2.8.5
 -----
 
-All:
-
-
-All (Unix):
-
-
-All (GUI):
-
-
 wxMSW:
+
+- Fix crash when destroying a default button (Tim Kosse)
 - Correct problem with page setup dialog when using landscape mode
 - Added msw.font.no-proof-quality system option, see manual for description
 - Fix appearance of notebook with non-top tabs under Windows Vista

src/common/wincmn.cpp

@@ -324,10 +324,27 @@ wxWindowBase::~wxWindowBase()
         wxTopLevelWindow *tlw = wxDynamicCast(wxGetTopLevelParent((wxWindow*)this),
                                               wxTopLevelWindow);
 
-        if ( tlw && tlw->GetDefaultItem() == this )
-            tlw->SetDefaultItem(NULL);
-        if ( tlw && tlw->GetTmpDefaultItem() == this )
-            tlw->SetTmpDefaultItem(NULL);
+        if ( tlw )
+        {
+            wxWindow* tmpDefaultItem = tlw->GetTmpDefaultItem();
+            if ( tmpDefaultItem == this )
+                tlw->SetTmpDefaultItem(NULL);
+            else if ( tmpDefaultItem )
+            {
+                // A temporary default item masks the real default item, so
+                // temporarily unset the temporary default item so we can access the
+                // real default item.
+                tlw->SetTmpDefaultItem(NULL);
+
+                if ( tlw->GetDefaultItem() == this )
+                    tlw->SetDefaultItem(NULL);
+
+                // Set the temporary default item back.
+                tlw->SetTmpDefaultItem(tmpDefaultItem);
+            }
+            else if ( tlw->GetDefaultItem() == this )
+                tlw->SetDefaultItem(NULL);
+        }
     }
 
     // reset the dangling pointer our parent window may keep to us