79a80,86
>     def _index(self, refChild):
>         if self._index_cache >= 0 and self._index_cache < len(self.childNodes) \
>            and self.childNodes[self._index_cache] == refChild:
>             return self._index_cache
>         self._index_cache = self.childNodes.index(refChild)
>         return self._index_cache
>             
95c102
<                 index = self.childNodes.index(refChild)
---
>                 index = self._index(refChild)
100a108
>             self._index_cache += 1
142c150
<             index = self.childNodes.index(oldChild)
---
>             index = self._index(oldChild)
332a341
>         self._index_cache = -1
649a659
>         self._index_cache = -1
1308a1319
>         self._index_cache = -1
1501a1513
>         self._index_cache = -1