ORA-01410 when UNION is present

Hello Folks,

I have a question regarding querying rows from a complex view (with a UNION), based on ROWID as the condition.

My View:

CREATE OR REPLACE VIEW APP_ATTRIBUTES AS

SELECT a.lu,

       a.lu_type lu_type_db,

       a.prompt,

       a.module,

       a.published_db,

       a.used_db,

       a.synchronized_db,

       NULL enabled_rowkey,

       a.objversion,

       a.objid,

       a.create_projection_db,

       a.note note

FROM   app_lus a

UNION

SELECT a.custom_field_lu    lu,

       b.lu_type lu_type_db,

       a.lu_prompt          prompt,

       a.module,

       a.published published_db,

       a.used used_db,

       a.synchronized synchronized_db,