Hi John

>Any effective ways to compare 2 collections, which can indicate which item was removed, which is added and which is still remain there (position can be ignore)?
>

It depends. Has an item in both collections got the same key? If so you can just use GETKEY() to see if it's there or not.

Otherwise you may be into using COMPOBJ() to see if an object in one collection is the same as any object in the other - that could be a tedious process if the collections are large.