Never, never, never sort the keys during a page write.

Reordering keys during write causes ObjIDs to be invalidated by writing
pages out. This means that users of tools like PRPShop have to click
save on specific PRP files in specific orders. For more information, see
pull request #218. The issue fixed here was introduced in ba1d890.

core/ResManager/plResManager.cpp

@@ -244,9 +244,6 @@ void plResManager::WritePage(hsStream* S, plPageInfo* page)
     std::vector<short> types = keys.getTypes(page->getLocation());
     page->setClassList(types);
 
-    if (preserveIDs)
-        keys.sortKeys(page->getLocation());
-
     page->write(S);
     page->setDataStart(S->pos());
     page->setNumObjects(WriteObjects(S, page->getLocation()));