From 9038e724d3e05a0ea4068f4b9de713eb79d9f0f9 Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Fri, 11 May 2007 13:04:33 +0000
Subject: [PATCH] don't try to update TLW default button in WM_SET/KILLFOCUS
 handlers if the TLW is being deleted (bug 1660913) [backport from HEAD]

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@45958 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---
 src/msw/button.cpp | 33 +++++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/msw/button.cpp b/src/msw/button.cpp
index 13f270d4c5..47970c1d51 100644
--- a/src/msw/button.cpp
+++ b/src/msw/button.cpp
@@ -357,12 +357,33 @@ void wxButton::SetDefault()
     SetDefaultStyle(this, true);
 }
 
+// special version of wxGetTopLevelParent() which is safe to call when the
+// parent is being destroyed: wxGetTopLevelParent() would just return NULL in
+// this case because wxWindow version of IsTopLevel() is used when it's called
+// during window destruction instead of wxTLW one, but we want to distinguish
+// between these cases
+static wxTopLevelWindow *GetTLWParentIfNotBeingDeleted(wxWindow *win)
+{
+    for ( ; win; win = win->GetParent() )
+    {
+        if ( win->IsBeingDeleted() )
+            return NULL;
+
+        if ( win->IsTopLevel() )
+            break;
+    }
+
+    wxASSERT_MSG( win, _T("button without top level parent?") );
+
+    return wxDynamicCast(win, wxTopLevelWindow);
+}
+
 // set this button as being currently default
 void wxButton::SetTmpDefault()
 {
-    wxTopLevelWindow *tlw = wxDynamicCast(wxGetTopLevelParent(this), wxTopLevelWindow);
-
-    wxCHECK_RET( tlw, _T("button without top level window?") );
+    wxTopLevelWindow * const tlw = GetTLWParentIfNotBeingDeleted(GetParent());
+    if ( !tlw )
+        return;
 
     wxWindow *winOldDefault = tlw->GetDefaultItem();
     tlw->SetTmpDefaultItem(this);
@@ -374,9 +395,9 @@ void wxButton::SetTmpDefault()
 // unset this button as currently default, it may still stay permanent default
 void wxButton::UnsetTmpDefault()
 {
-    wxTopLevelWindow *tlw = wxDynamicCast(wxGetTopLevelParent(this), wxTopLevelWindow);
-
-    wxCHECK_RET( tlw, _T("button without top level window?") );
+    wxTopLevelWindow * const tlw = GetTLWParentIfNotBeingDeleted(GetParent());
+    if ( !tlw )
+        return;
 
     tlw->SetTmpDefaultItem(NULL);