A very annoying bug that has apparently been around for ages and never been solved:
When you have a lookup field (nondatabase) with an LOV and set ‘validate-from-lov’ to true, your blockstatus is set to ‘CHANGED’ when you fill the lookup in the post_query trigger.
This is silly because you are changing nondatabase items. The following post shows that this has been a problem since 2000:
http://forums.oracle.com/forums/thread.jspa?messageID=253582
I found a document on metalink about this, which is dated 31 oct 2007.
I tested the solution provided in the document and it works!