Don't use invalid pointer in file dialog hook procedure in wxMSW.

We can receive WM_NOTIFY for other than CDN_XXX messages if we have a native
control as our immediate child (which can happen with "extra" controls) and
the LPARAM is not a pointer to OFNOTIFY at all in this case, so don't try to
use it as such.

This fixes a crash when adding a "bare" extra control, see #16003.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75937 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/filedlg.cpp

@@ -171,6 +171,9 @@ wxFileDialogHookFunction(HWND      hDlg,
 #endif // __WXWINCE__
 
         case WM_NOTIFY:
+            {
+                NMHDR* const pNM = reinterpret_cast<NMHDR*>(lParam);
+                if ( pNM->code >= CDN_FIRST && pNM->code < CDN_LAST )
                 {
                     OFNOTIFY* const
                         pNotifyCode = reinterpret_cast<OFNOTIFY *>(lParam);
@@ -190,6 +193,7 @@ wxFileDialogHookFunction(HWND      hDlg,
                             break;
                     }
                 }
+            }
             break;
 
         case WM_DESTROY: