From a71b5697ad1d540305512bdac093adce2e219cd2 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Mon, 19 Oct 2009 14:01:34 +0000
Subject: [PATCH] fix drag-and-drop window traversal to handle menus and other
 unrealized windows

svn: r16365
---
 src/wxxt/src/Windows/Window.cc | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/src/wxxt/src/Windows/Window.cc b/src/wxxt/src/Windows/Window.cc
index ecfef4f77d..4835a77cfc 100644
--- a/src/wxxt/src/Windows/Window.cc
+++ b/src/wxxt/src/Windows/Window.cc
@@ -2513,19 +2513,22 @@ wxWindow *wxWindow::FindChildByWidget(Widget w)
   wxChildNode *node, *next;
   wxWindow *r;
 
-  if ((w == X->frame)
-      || (w == X->handle))
-    return this;
+  if (X) {
+    if ((w == X->frame)
+        || (w == X->handle))
+      return this;
+  }
 
-
-  for (node = children->First(); node; node = next) {
-    wxWindow *child;
-    next = node->Next();
-    child = (wxWindow*)(node->Data());
-    if (child) {
-      r = child->FindChildByWidget(w);
-      if (r)
-        return r;
+  if (children) {
+    for (node = children->First(); node; node = next) {
+      wxWindow *child;
+      next = node->Next();
+      child = (wxWindow*)(node->Data());
+      if (child) {
+        r = child->FindChildByWidget(w);
+        if (r)
+          return r;
+      }
     }
   }