I have just altered a VCL class in Delphi 5. This article will keep track of anything I change and why.
Make sure that the folder is in your library path or the altered units will not get compiled.
When using a TCollection with thousands of items, freeing the collection can take quite a while (10 seconds on my Duron 700 for 3000 items).
in Classes.pas change
procedure TCollection.RemoveItem(Item: TCollectionItem);
NotifyDesigner(Self, Item, opRemove);
Count := FItems.Count;
if (Count > 0) and (Item = FItems[Count - 1]) then
FItems.Delete(Count - 1)
Item.FCollection := nil;