I can't remember what caused this crash, I think it might have had to do with not having a style sheet or something. In any case, we're dereferencing a null pointer when we shouldn't be. Attaching the patch

Please take a look.

This patch is nonsensical. The code is already conditioned against "aChild" being null at the beginning of the method and there is no code that changes it. If the app really crashed there, it must have been due to memory corruption. Do you have a recipe or test case?

huh, I don't think that check was in there when I made the patch. wierd!

The check's been there since November 98. If you really saw a crash there, I'd like to know how it happened, or perhaps it was another method?

Actually, the more I look at it, I think I made the original patch because aChild->mPrevSibling or aChild->mNextSibling was null, and added the extra "if (aChild) " just to be careful. If I remember right about what caused this, I believe a CSS file was missing that was specified in the XML header, and I had already fixed another crasher by checking for null elsewhere in my tree, which put the linked list in some wierd state. (I think the other crash fix went into another bug/patch)